Relational Database Service. User Guide. Issue 05 Date

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1 Issue 05 Date

2 Contents Contents 1 Introduction Concepts RDS DB Cluster DB Instance DB Backup DB Snapshot RDS DB Instances DB Instance Specifications DB Engines and Versions DB Instance Status Accessing RDS System Architecture Application Scenarios Limitations Security Suggestions Relationship Between the RDS and Other Services Quick Start Before You Apply Creating RDS DB Instances Creating RDS MySQL DB Instances Creating RDS PostgreSQL DB Instances Connect to RDS DB Instances Connecting to RDS MySQL DB Instances Connecting to RDS PostgreSQL DB Instances Migrating Data Preparing for Data Migration Exporting Data Importing Data DB Instance Lifecycle Management Backing Up and Restoring Data Automatically Backing Up Data...20 Issue 05 ( ) ii

3 Contents Creating a Snapshot Restoring a DB Instance to a Specified Time Point Restoring a Snapshot Replicating a Snapshot Deleting a Snapshot Adding a Read Replica Setting Configuration Parameters Scaling Up Storage Space Modifying the DB Instance Class Rebooting a DB Cluster or a DB Instance Deleting a DB Cluster or a Read Replica Monitoring RDS Monitoring Resources Through CES Viewing Logs RDS MySQL Configuring Database Security Setting Configuration Parameters Migrating Data Preparing for Data Migration Exporting Data Importing Data Restoring a DB Instance to a Specified Time Point Restoring a Snapshot Monitoring Metrics Viewing Logs Viewing Error Logs Viewing Slow Query Logs RDS PostgreSQL Configuring Database Security Setting Configuration Parameters Migrating Data Preparing for Data Migration Exporting Data Importing Data Restoring a DB Instance to a Specified Time Point Restoring a Snapshot Monitoring Metrics Viewing Recent Logs FAQs Common FAQs What Precautions Should Be Taken When Using RDS?...46 Issue 05 ( ) iii

4 Contents What Is the Availability of RDS DB Instances? Can I Use a Template to Create RDS DB Instances? What Are the Differences Between RDS and Other Database Solutions? Will My RDS DB Instances Be Affected by Other Users' RDS DB Instances? How Many RDS DB Instances Can RDS Run? How Many Databases Can Run in an RDS DB Instance? Management FAQs What Can I Do About Websites Becoming Slower to Respond after Using RDS? What Should I Do If My Query Is Slow? What Is the Time Delay Between Primary/Standby Synchronization? How Do I Identify Data Corruption? Why Is a Table Missing or Data Deleted from My Database? Can Multiple ECSs Connect to the Same RDS DB Instance? What Happens to the RDS Database Backup After the RDS DB Instance Is Deleted? Will My Backups Be Deleted If I Close My Cloud Account? Are My RDS DB Instances Available During Scaling? Does RDS Support Read/Write Splitting? Connection and Access FAQs Can an External Server Access the RDS Database? What Does "Number of RDS DB Connections" Mean? What Should I Do If the ECS Cannot Connect to the RDS DB Instance? What Should I Do If a Database Client Problem Causes a Connection Failure? What Should I Do If an RDS DB Instance Problem Causes a Connection Failure? How Can My Applications Access an RDS DB Instance in a VPC? Do Applications Need to Support Automatic Reconnection to the RDS DB Instance? What Types of DB Engines Does RDS Support for Importing? Why Do I Need to Use the mysqldump or pg_dump Tool for Migration? How Can I Install the MySQL Client? How Can I Install the PostgreSQL Client? Parameter and Metrics FAQs What Parameters Can I Modify on the RDS Console (MySQL)? What Parameters Can I Modify on the Console (PostgreSQL)? What Inappropriate Parameter Settings Cause Unavailability of the Database? What DB Instance Monitoring Metrics Do I Need to Pay Attention To? Network and Security FAQs What Security Protection Policies Does the RDS Have? Why Do I Need to Use the RDS DB Instance in VPC? Why Do I Need to Use a Database Subnet? How Do I Ensure Security of RDS DB instances in a VPC? Storage FAQs What Storage Engines Does RDS for MySQL Support? How Do I Back Up the RDS Database to the ECS?...81 Issue 05 ( ) iv

5 Contents How Long Does RDS Store Backup Data For? Can My Database Be Used in the Backup Window? What Is the Hardware Configuration for the Database Storage of RDS DB Instances? What Should I Do If My Data Exceeds the Database Storage Space of an RDS DB Instance? Which Items Occupy the Storage Space of My Purchased RDS DB Instances? What Is the Overhead of the Data Disk I Applied for When I Created an RDS DB Instance? Which Types of Logs and Files Occupy the Database Storage Space of RDS DB Instances? A Change History B Glossary Issue 05 ( ) v

6 1 Introduction 1 Introduction Before using the Relational Database Service (RDS), you need to have a general knowledge about it, including its applicable scenarios, functions, and restrictions. Issue 05 ( ) 1

7 1 Introduction 1.1 Concepts RDS The Relational Database Service (RDS) is a cloud-based online relational database service. RDS is stable, reliable, scalable, and easy to manage. You can start using it right after purchasing it. RDS provides a comprehensive performance monitoring system, multi-level security protection measures, and a professional database management platform, allowing you to easily set, operate, and extend the relational database. On the RDS console, you can execute almost all mandatory tasks without programming, which simplifies the operation procedure and reduces routine O&M workload, helping you focus on application development and service development. Users access the RDS database instance (DB instance) through an Elastic Cloud Server (ECS). The following figure shows the details DB Cluster DB Instance Currently, you can only access RDS DB instances from an ECS in the same Virtual Private Cloud (VPC) in an internal network. You may be able to access them through the Internet in the future. The RDS manages DB instances in DB clusters. A DB cluster consists of multiple DB instances. A DB cluster must contain a primary DB instance, and can contain a standby DB instance and several read replicas. The DB instances in a DB cluster work together to provide database services. An RDS DB instance is the minimum management unit of RDS. An RDS DB instance represents a relational database running independently. DB instances come in three types: Primary DB instance Standby DB instance Read replica Users can create and manage DB instances of various DB engines in the RDS system. Issue 05 ( ) 2

8 1 Introduction DB Backup DB Snapshot DB backup refers to the replication of data in database systems. If a disaster or misoperation occurs, you can use the data copies to restore system data. A DB snapshot is a user-initiated snapshot of your DB instance, backing up the entire DB instance and not just individual databases. DB snapshots enable you to back up your DB instance in a known state as frequently as you wish, and then restore to that specific state at any time. You can create DB snapshots on the RDS console or using RDS application programming interfaces (APIs). DB snapshots exist until you delete them or until you delete the DB instances which the snapshots belong to on the RDS console or using an RDS API. 1.2 RDS DB Instances DB Instance Specifications Table 1-1 DB instance specifications DB Instance Class Number of vcpus Memory (GB) db.s1.medium 1 4 db.s1.large 2 8 db.s1.xlarge 4 16 db.s1.2xlarge 8 32 db.c2.medium 1 2 db.c2.large 2 4 db.c2.xlarge 4 8 db.m1.large 2 16 db.m1.xlarge 4 32 db.m1.2xlarge DB Engines and Versions Currently, RDS supports the DB engines and versions shown in Table 1-2. Other database versions and different types of DB engines will be supported in the future. Issue 05 ( ) 3

9 1 Introduction Table 1-2 DB engine and versions DB Engine Version MySQL PostgreSQL DB Instance Status DB Instance Status Table 1-3 Status and description DB Instance Status Available Faulty Creating Rebooting Restoring Modifying Description A DB instance is available. A DB instance is faulty. A DB instance or snapshot is being created. A DB instance is being rebooted because of a customer request or a modification that requires rebooting the DB instance. An automated backup DB instance or snapshot is being restored. The CPU or memory of a DB instance is being modified. Instance Space Usage The space usage of RDS DB instances whose status is Available is monitored in real time. Table 1-4 Status and description Status Description Idle The RDS DB instance storage space usage is lower than 50%. Warning The RDS DB instance storage space usage is greater than or equal to 50% and less than 80%. Danger The RDS DB instance storage space usage is greater than or equal to 80%. You are advised to scale your RDS DB instance as soon as possible. Exception The RDS DB instance storage space usage is unknown. Issue 05 ( ) 4

10 1 Introduction 1.3 Accessing RDS The RDS provides web-based service management platforms, including the management console and HTTPS-based APIs for you to access RDS. There are two ways to access RDS: Through the management console You can log in to the management console to perform operations on RDS. If you have registered an account, you can access RDS by logging in to the management console and selecting Relational Database Service from the console homepage. Through APIs 1.4 System Architecture If you need to integrate RDS into a third-party system for secondary development, you can use the API to access RDS. For details, see Relational Database Service API Reference. This section describes the RDS system architecture, interconnected systems, and service operation procedure. Issue 05 ( ) 5

11 1 Introduction Portal Home: Unified web portal for the public cloud. After you log in and select RDS, you will be redirected to the RDS console. RDS console: Self-service management console for RDS web users. You can input parameters required in instance management commands. For example, when creating an instance, you can set the DB engine and version, instance specifications, storage size, and automatic backup policy. RDS service: RDS backend service, which handles instance creation, configuration, and other management operations. In most cases, RDS service issues management commands to the RDS DB instance for execution. When RDS service needs to obtain computing resources, such as when you are creating an instance, RDS service invokes IaaS-layer services to apply for resources. ECS, EVS, and VPC: Services on the IaaS layer, providing elastic computing, storage, and network resources. The RDS applies for resources from these services to build a running environment for DB instances. RDS DB instance: includes database engines and other necessary tools, such as backup tools. After you create and initialize a DB instance, applications in other ECSs can connect to the instance to read and write data. Cloud Eye (CES): Metric monitoring service. An RDS DB instance regularly reports instance running status to the CES. The CES stores and displays status data and reports alarms when the metrics of the DB instance exceed your specified thresholds. Object Storage System (OBS): Provides object storage services. RDS uses the OBS service to store DB instance backup files. 1.5 Application Scenarios 1.6 Limitations RDS applies to database applications in various industries. RDS can be used for the Internet industry, such as mobile games, online games, e-commerce, e-government, enterprise portals, social networks, and social media. RDS can also be used for enterprise office applications, Software as a Service (SaaS), and other business systems, and can even provide backend data to support software developers in software development and testing. An RDS DB instance must be created within the VPC subnet. Only applications in the subnet where the RDS DB instance locates can access the DB instance. An RDS read replica must be created in the subnet where the primary DB instance locates. The operating system (OS) for DB instances is invisible to you. Your applications can only access the IP addresses and ports corresponding to the database. ECSs used for RDS and backup files stored on the OBS are invisible to you. They are only visible in the RDS backend management system. 1.7 Security Suggestions Consider data encryption, connection encryption, and database account security to ensure data security. Issue 05 ( ) 6

12 1 Introduction Data Encryption Connection Encryption Database Account Security Before saving sensitive information and private data in a database, you are advised to encrypt them to reduce the risk of information leakage. You are advised to connect an application to a DB instance via SSL to enhance data transmission security. For details on MySQL account security configurations, see 5.1 Configuring Database Security. For details on PostgreSQL account security configurations, see 6.1 Configuring Database Security. 1.8 Relationship Between the RDS and Other Services VPC OBS CES The VPC implements network isolation and access control for your RDS DB instances. The OBS stores tenants' RDS DB instance backup data and snapshot data. CES is an open monitoring platform, monitoring RDS and relevant resources. The CES supports multiple alarm modes to ensure timely prewarning and normal service running. Issue 05 ( ) 7

13 2 Quick Start 2 Quick Start 2.1 Before You Apply Before applying for an RDS DB instance, make preparations to ensure smooth application. Evaluating DB Instance Specifications To effectively support your application with the RDS you are to apply for, evaluate the computing and storage capabilities required for your application, and consider your service types and website size to decide DB instance specifications accordingly. The DB instance specifications mainly include CPU/memory, storage type, and storage space. Choosing an AZ To reduce delay between your application and the RDS, you are advised to put them in the same available zone (AZ). Determining a VPC VPC provides a logically isolated network. An RDS DB instance must be created within the VPC subnet. An RDS read replica must be created in the subnet where the primary DB instance locates. To improve security, you are advised to put your application and the RDS in the same VPC for management. Determining Whether an HA System Is Required The RDS provides a high availability (HA) solution to prevent services from being affected by faults on the primary DB instance. You can choose whether to create a standby DB instance when creating a primary one. The standby DB instance incurs additional costs. 2.2 Creating RDS DB Instances Issue 05 ( ) 8

14 2 Quick Start Creating RDS MySQL DB Instances You can take the computing capability and storage space into consideration to customize an RDS based on service requirements. RDS allows a tenant to create a maximum of 20 RDS DB instances. Procedure Step 1 Log in to Console Home. Step 2 Click and choose Database > Relational Database Service to navigate to the RDS console. Step 3 Step 4 Click Create DB Instance on the Dashboard tab page. On the Specify Details page, specify DB instance specifications, network, database configuration, HA, and the backup policy. Click Create Now. Table 2-1 Instance specifications Parameter DB Instance Name DB Engine Database Version DB Instance Class Storage Description The DB instance name must be 4 to 64 characters in length and start with a letter. It is case-insensitive, and can contain only letters, digits, or hyphens (-). MySQL (recommended) For details, see DB Instance Specifications. RDS supports the following storage types: Common I/O (SATA) and Ultrahigh I/O (SSD). The storage space ranges from 100 GB to 2,000 GB. Table 2-2 Network Parameter AZ VPC Description A region consists of multiple AZs, where resources use independent power supply and networks. AZs are physically isolated but interconnected through the internal network. The VPC which an RDS DB instance belongs to implements network isolation for different instances. You need to create or select the required VPC. For details on how to create a VPC, see "Creating a VPC" in Virtual Private Cloud. Issue 05 ( ) 9

15 2 Quick Start Parameter Subnet Security Group Description A subnet provides dedicated network resources that are logically isolated from other networks, improving network security. The subnet only takes effect within the AZ. A security group restricts secure access rules to enhance security when RDS and other services access each other. To allow standby DB instances and read replicas to synchronize data with primary DB instances, select a security group that allows machines in the cluster to access each other. (For example, select the TCP protocol, inbound direction, use the given port number 8635, and set the source address to the address of the subnet or the security group which the cluster belongs to.) Table 2-3 Database Configuration Parameter Administrator Password Confirm Password Database Port Description The default login name for the database is root. The password is a string of 8 to 32 characters. It must contain uppercase letters, lowercase letters, digits, and special characters. You can use the following special characters: ~!@#%^*-_=+? The value of this parameter must be the same as that of Administrator Password by default. Currently the port cannot be changed. Table 2-4 HA Parameter Click to enable HA. Synchronization Mode Description This parameter specifies whether a primary DB instance is created with a standby DB instance to ensure cluster HA. Enable HA if you want to create a standby DB instance. Two fixed IP addresses are allocated for the primary and standby RDS DB instances, but they are accessed using a floating IP. You can log in to the RDS console, and use the floating IP address displayed in the Connection Address column of the corresponding primary DB instance to connect the DB instance to the database. Do not delete the floating IP address from the subnet. The value of this parameter can be Asynchronous or Semisynchronous. The default value is Asynchronous. For details about synchronization, see the glossary or the official explanation at dev.mysql.com/doc/refman/5.6/en/replication-semisync.html. Issue 05 ( ) 10

16 2 Quick Start Table 2-5 Backup Policy Parameter Automated Backup Retention Period (Days) Backup Start Time Description If the automated backup policy is enabled, an automated full backup is triggered. If the automated backup policy is disabled, RDS DB instances are not automatically backed up. For details on enabling or modifying the automated backup policy, see Automatically Backing Up Data. The value range is 1 to 35. Increasing the retention period improves data reliability but costs more. Set the retention period as needed. Every day, the backup starts within one hour after the backup start time you set. The backup end time depends on the amount of data to be backed up. Price calculator: used to query the costs of current configurations. The performance of an RDS DB instance you applied for depends on the configuration you selected for it. Hardware configuration items include the instance specification, storage type, and storage space. The better I/O you select for Storage, the higher the read/write speed that the primary DB instance can achieve. You can scale the storage space after the RDS DB instance is created. Step 5 Step 6 On the Confirm Specifications page, confirm the specifications. To modify your settings, click Back to modify RDS DB instance information. If you do not need to modify your settings, click Submit to complete RDS DB instance application. After an RDS DB instance is created, you can view and manage it on the Instance Mgmt tab page. 1. RDS DB instance creation takes about 15 minutes. During creation, the instance status displayed in Instance List is Creating. 2. The DB instance is created with a status of Available. ----End Creating RDS PostgreSQL DB Instances Procedure You can take the computing capability and storage space into consideration to customize an RDS based on service requirements. RDS allows a tenant to create a maximum of 20 RDS DB instances. Step 1 Log in to Console Home. Step 2 Click and choose Database > Relational Database Service to navigate to the RDS console. Issue 05 ( ) 11

17 2 Quick Start Step 3 Step 4 Click Create DB Instance on the Dashboard tab page. On the Specify Details page, specify DB instance specifications, network, database configuration, HA, and the backup policy. Click Create Now. Table 2-6 DB Instance Specifications Parameter DB Instance Name DB Engine Database Version DB Instance Class Storage Description The DB instance name must be 4 to 64 characters in length and start with a letter. It is case-insensitive, and can contain only letters, digits, or hyphens (-). PostgreSQL For details, see DB Instance Specifications. RDS supports the following storage types: Common I/O (SATA) and Ultrahigh I/O (SSD). The storage space ranges from 100 GB to 2,000 GB. Table 2-7 Network Parameter AZ VPC Subnet Security Group Description A region consists of multiple AZs, where resources use independent power supply and networks. AZs are physically isolated but interconnected through the internal network. The VPC which an RDS DB instance belongs to implements network isolation for different instances. You need to create or select the required VPC. For details on how to create a VPC, see "Creating a VPC" in Virtual Private Cloud. A subnet provides dedicated network resources that are logically isolated from other networks, improving network security. The subnet only takes effect within the AZ. A security group restricts secure access rules to enhance security when RDS and other services access each other. To allow standby DB instances and read replicas to synchronize data with primary DB instances, select a security group that allows machines in the cluster to access each other. (For example, select the TCP protocol, inbound direction, use the given port number 8635, and set the source address to the address of the subnet or the security group which the cluster belongs to.) Issue 05 ( ) 12

18 2 Quick Start Table 2-8 Database Configuration Parameter Administrator Password Confirm Password Database Port Description The default login name for the database is root. The password is a string of 8 to 32 characters. It must contain uppercase letters, lowercase letters, digits, and special characters. You can use the following special characters: ~!@#%^*-_=+? The value of this parameter must be the same as that of Administrator Password by default. Currently the port cannot be changed. Table 2-9 HA Parameter Click to enable HA. Synchronizatio n Mode Description This parameter specifies whether a primary DB instance is created with a standby DB instance to ensure cluster HA. Enable HA if you want to create a standby DB instance. Two fixed IP addresses are allocated for the primary and standby RDS DB instances, but they are accessed using a floating IP. You can log in to the RDS console, and use the floating IP address displayed in the Connection Address column of the corresponding primary DB instance to connect the DB instance to the database. Do not delete the floating IP address from the subnet. The value of this parameter can be Asynchronous or Synchronous. The default value is Asynchronous. For details about synchronization, see the glossary or the official explanation at docs/current/static/warm-standby.html#synchronous- REPLICATION. Table 2-10 Backup Policy Parameter Automated Backup Retention Period (Days) Description If the automated backup policy is enabled, an automated full backup is triggered. If the automated backup policy is disabled, RDS DB instances are not automatically backed up. For details on enabling or modifying the automated backup policy, see Automatically Backing Up Data. The value range is 1 to 35. Increasing the retention period improves data reliability but costs more. Set the retention period as needed. Issue 05 ( ) 13

19 2 Quick Start Parameter Backup Start Time Description Every day, the backup starts within one hour after the backup start time you set. The backup end time depends on the amount of data to be backed up. Price calculator: used to query the costs of current configurations. The performance of an RDS DB instance you applied for depends on the configuration you selected for it. Hardware configuration items include the instance specification, storage type, and storage space. The better I/O you select for Storage, the higher the read/write speed that the primary DB instance can achieve. You can scale the storage space after the RDS DB instance is created. Step 5 Step 6 On the Confirm Specifications page, confirm the specifications. To modify your settings, click Back to modify RDS DB instance information. If you do not need to modify your settings, click Submit to complete RDS DB instance application. After an RDS DB instance is created, you can view and manage it on the Instance Mgmt tab page. 1. RDS DB instance creation takes about 15 minutes. During creation, the instance status displayed in Instance List is Creating. 2. The DB instance is created with a status of Available. ----End 2.3 Connect to RDS DB Instances You can only access RDS through an ECS. You can maintain RDS DB instances through a database client on the ECS. You can connect to DB instances through a database client using a common connection or Secure Sockets Layer (SSL) connection. The SSL connection is encrypted and more secure. When an RDS DB instance is created, the RDS creates an SSL for the RDS DB instance. If SSL certificate authentication is enabled to avoid spoofing attacks, the SSL certificate contains a common name (CN), which is the name of the RDS DB instance device node. You are advised to connect an application to a DB instance via SSL to enhance data transmission security. For details on how to create an ECS, see Step 1. For details on how to connect to the ECS, see "Logging in to an ECS" in Elastic Cloud Server. For details on how to obtain and install the MySQL installation package, see How Can I Install the MySQL Client? For details on how to obtain and install the PostgreSQL installation package, see How Can I Install the PostgreSQL Client? Issue 05 ( ) 14

20 2 Quick Start Connecting to RDS MySQL DB Instances Prerequisites Common Connection You can connect to DB instances through the MySQL client using a common connection or SSL connection. The SSL connection is encrypted and more secure. An ECS has been created and a MySQL client has been installed. Step 1 Step 2 Connect to the ECS. Connect to an RDS DB instance. mysql -h <host_name> -P u <User> -p SSL Connection -h indicates the IP address of the primary DB instance, that is, Connection Address of the primary DB instance in the DB instance list of the corresponding cluster on the Instance Mgmt tab page. -P indicates the port number (8635 by default). -u indicates the user name, that is, the RDS database account. (The default administrator account is root.) -p indicates the password of the database account. Use user root to connect to a DB instance. The example is as follows: mysql -h P u root -p ----End Step 1 On the Instance Mgmt tab page, click MySQL to download the root certificate used for all regions. Figure 2-1 Downloading the root certificate Step 2 Step 3 Connect to the ECS. Connect to an RDS DB instance. In Linux, for example, run the following command: mysql -h<hostname> -P8635 -u<username> -p --ssl-ca=ca.crt -u indicates the user name, that is, the RDS database account. (The default administrator account is root.) -p indicates the password of the database account. -h indicates the IP address of the primary DB instance, that is, Connection Address of the primary DB instance in the DB instance list of the corresponding cluster on the Instance Mgmt tab page. -P indicates the port number (8635 by default). --ssl-ca indicates the SSL certificate file name. Use user root to connect to a DB instance via SSL. The example is as follows: Issue 05 ( ) 15

21 2 Quick Start mysql -h P8635 -uroot -p --ssl-ca=ca.crt ----End Connecting to RDS PostgreSQL DB Instances You can connect to DB instances through the PostgreSQL client using a common connection or SSL connection. The SSL connection is encrypted and more secure. Prerequisites An ECS has been created and a PostgreSQL client has been installed. Common Connection Step 1 Step 2 Connect to the ECS. Connect to an RDS DB instance. psql --no-readline -U <user> -p <port> -h <host> -d <datastore> -W -h indicates the IP address of the primary DB instance, that is, Connection Address of the primary DB instance in the DB instance list of the corresponding cluster on the Instance Mgmt tab page. -p indicates the port number (8635 by default). -U indicates the user name, that is, the RDS database account. (The default administrator account is root.) -d indicates the name of the database to be connected. (The default database name is postgres.) -W indicates the password forcibly to be input for the connection. After running the command, enter the password of the database account. Use user root to connect to a postgres DB instance. The example is as follows: psql --no-readline -U root -p h d postgres -W ----End SSL Connection Step 1 On the Instance Mgmt tab page, click PostgreSQL to download the root certificate used for all regions. Figure 2-2 Downloading the root certificate Step 2 Step 3 Connect to the ECS. Connect to an RDS DB instance. In Linux, for example, run the following command: psql --no-readline -h <host> -p <port> "dbname=<database> user=<user> password=<password> sslmode=verify-full sslrootcert=<ca.pem>" Issue 05 ( ) 16

22 2 Quick Start -h indicates the IP address of the primary DB instance, that is, Connection Address of the primary DB instance in the DB instance list of the corresponding cluster on the Instance Mgmt tab page. -p indicates the port number (8635 by default). dbname indicates the name of the database to be connected. (The default database name is postgres.) user indicates the user name, that is, the RDS database account. (The default administrator account is root.) password indicates the login password of the user. sslmod indicates the SSL connection mode (full authentication mode by default). sslrootcert indicates the path of the ssl connection CA certificate. Use user root to connect to a postgres DB instance via SSL. The example is as follows: psql --no-readline -h p 8635 "dbname=postgres user=root sslmode=verify-full sslrootcert=/root/ca.pem" Step 4 After you log in to the PostgreSQL database, the following information is displayed, indicating the DB instance is connecting to the PostgreSQL database through SSL. SSL connection (protocol: TLSv1.2, cipher: ECDHE-RSA-AES256-GCM-SHA384, bits: 256, compression: off) ----End 2.4 Migrating Data Data migration refers to the migration of existing data from a local database to RDS. You can only access RDS through ECSs. When you import the existing data from a database to RDS, use a tool to dump the database, and import the dump files to RDS through the ECS. For details on migrating data from a MySQL database to RDS, see 5.3 Migrating Data. For details on migrating data from a PostgreSQL database to RDS, see 6.3 Migrating Data Preparing for Data Migration Exporting Data You can access RDS through an ECS only. Before migration, create an ECS and install a database dump tool. For details on preparations for migrating data from a MySQL database to RDS, see Preparing for Data Migration. For details on preparations for migrating data from a PostgreSQL database to RDS, see Preparing for Data Migration. RDS supports logical migration. To dump data into an SQL file on a machine, you need to use a database dump tool. Issue 05 ( ) 17

23 2 Quick Start NOTICE The dump tool should map to the DB engine version. The database migration is performed offline. Before the migration, stop any application using the source database Importing Data For details on exporting data from a MySQL database to RDS, see Exporting Data. For details on exporting data from a PostgreSQL database to RDS, see Exporting Data. Use a client to connect to an RDS DB instance to import data through the ECS. The dump tool should map to the database engine version. For details on importing data from a MySQL database to RDS, see Importing Data. For details on importing data from a PostgreSQL database to RDS, see Importing Data. Issue 05 ( ) 18

24 3 DB Instance Lifecycle Management 3 DB Instance Lifecycle Management Lifecycle management of RDS DB instances includes creating, modifying, rebooting, backing up, and restoring a DB instance. Issue 05 ( ) 19

25 3 DB Instance Lifecycle Management 3.1 Backing Up and Restoring Data RDS supports DB instance backup and restoration to ensure data reliability Automatically Backing Up Data RDS backs up data based on automatic backup policies. RDS automatically backs up data in a database at the instance level. The backup will incur certain cost. If the database is faulty or data is damaged, you can restore it with the backup data to ensure data security. Automated backup data can be stored for the duration you specify. Backups are saved as packages in the OBS to ensure the confidentiality and durability of your data. You can set the automated backup policy to use the RDS automated backup function, or disable the automated backup policy to disable the function. Enabling the Automated Backup Policy Step 1 On the Instance Mgmt tab page, select a DB cluster and a DB instance in its DB instance list. In the Operation column of the selected primary DB instance, click Manage. Step 2 Click Backup & Restore and. Step 3 Set Retention Period (Days) and Backup Start Time, and click OK to complete the setting. ----End Before starting an automated backup, RDS checks existing backup files. If the retention period of a file does not comply with the backup retention period limit in the backup policy you set, the file is deleted. If the automated backup policy is enabled, an automated full backup is immediately triggered. Every day, the backup starts within one hour after the backup start time you set. The backup end time depends on the amount of data to be backed up. The value range for Retention Period (Days) is 1 to 35. Modifying the Automated Backup Policy Step 1 Step 2 Step 3 On the Instance Mgmt tab page, select a DB cluster and a DB instance in its DB instance list. In the Operation column of the selected primary DB instance, click Manage. Click Backup & Restore and Modify to modify the backup policy you have set. Reducing the retention period in the backup policy deletes expired automatically backed up data. Increasing the retention period improves data reliability. Set the retention period as needed. Click OK to save the modification. ----End Issue 05 ( ) 20

26 3 DB Instance Lifecycle Management Disabling an Automated Backup Policy Step 1 On the Instance Mgmt tab page, select a DB cluster and a DB instance in its DB instance list. In the Operation column of the selected primary DB instance, click Manage. Step 2 Click the Backup & Restore tab, and click to disable the policy. ----End Creating a Snapshot After you disable the automated backup policy, all the existing automated backup files are deleted and no longer billed. The RDS allows you to create snapshots of running primary DB instances. You can restore data using the snapshots, ensuring data HA. Method 1 A tenant can have a maximum of 50 snapshots in total. To increase this quota, contact the administrator. Step 1 Step 2 On the Instance Mgmt tab page, select a cluster. In the Operation column of its primary DB instance, choose More > Create Snapshot. Name the snapshot, and click OK. The snapshot name must be 4 to 64 characters in length and start with a letter. It is caseinsensitive, and can contain only letters, digits, or hyphens (-). Step 3 After the snapshot is created, you can view and manage it on the Snapshot Mgmt tab page. ----End Method 2 Step 1 Step 2 Step 3 On the Snapshot Mgmt page, click Create Snapshot. Select a primary DB instance and name its snapshot. Click OK to create the snapshot. 1. The instance name must be the name of an available primary DB instance. 2. The snapshot name must be 4 to 64 characters in length and start with a letter. It is caseinsensitive, and can contain only letters, digits, or hyphens (-). After the snapshot is created, you can view and manage it on the Snapshot Mgmt tab page. ----End Restoring a DB Instance to a Specified Time Point For details on restoring a MySQL DB instance to a specified time point, see 5.4 Restoring a DB Instance to a Specified Time Point. For details on restoring a PostgreSQL DB instance to a specified time point, see 6.4 Restoring a DB Instance to a Specified Time Point. Issue 05 ( ) 21

27 3 DB Instance Lifecycle Management Restoring a Snapshot For details on restoring a MySQL snapshot, see 5.5 Restoring a Snapshot. For details on restoring a PostgreSQL snapshot, see 6.5 Restoring a Snapshot Replicating a Snapshot Procedure You can replicate a snapshot to create a copy with the same content but a different name. Step 1 Step 2 Step 3 On the Snapshot Mgmt tab page, click the snapshot to be replicated, and click Replicate. Name the new snapshot, and click OK. After the new snapshot is created, you can view and manage it on the Snapshot Mgmt tab page. ----End Deleting a Snapshot Procedure You can delete RDS snapshots as needed. Step 1 On the Snapshot Mgmt tab page, find the snapshot to be deleted, and click Delete in the Operation column. You cannot delete a snapshot that is being restored. Step 2 Click OK to delete the snapshot. A deleted snapshot cannot be restored. ----End 3.2 Adding a Read Replica A read replica is used to enhance the read capability of an RDS DB cluster. Users can read from the read replica instead of the primary DB instance. After you create an RDS DB instance, you can create its read replicas as needed. This will incur certain costs. The CPU/memory of a read replica can be changed. The read replica's storage space and storage type are the same as those of its primary DB instance. Procedure A maximum of five read replicas can be created for one RDS DB cluster. Step 1 Select a DB cluster on the Instance Mgmt tab page. In the DB Instance List area, click More > Create Read Replica in the Operation column of the primary DB instance of this DB cluster. The Specify Details page is displayed. Issue 05 ( ) 22

28 3 DB Instance Lifecycle Management Step 2 On the Specify Details page, set Read Replica Name and DB Instance Class for the read replica, and click Create Now. Step 3 Step 4 Check specifications on the Confirm Specifications page. If you do not need to modify your settings, click Submit to submit the read replica creation application. To modify your settings, click Back to modify RDS DB instance information on the Specify Details page. After a read replica is created, you can select the DB cluster which the read replica belongs to on the Instance Mgmt tab page, and check and manage read replicas in the DB cluster in the DB instance list. ----End 3.3 Setting Configuration Parameters For details on setting configuration parameters for a MySQL DB instance, see 5.2 Setting Configuration Parameters. For details on setting configuration parameters for a PostgreSQL DB instance, see 6.2 Setting Configuration Parameters. 3.4 Scaling Up Storage Space If the storage space of your DB instances is insufficient, you can apply for scaling up it. With increasing service data, the amount of storage space that was originally applied for may be insufficient. In this case, apply for scaling up the RDS DB cluster or DB instance. Scaling Up a DB Cluster You can scale up a DB cluster only if the storage space of its instances is the same. You can scale up an RDS DB instance a maximum of four times. If you scale up a primary DB instance, its standby DB instance is scaled up at the same time. If the capacities of the primary and standby DB instances are the same, you can scale up the primary DB instance. If the standby DB instance is faulty, you cannot scale up the primary DB instance. You cannot reboot or delete the DB instance when scaling up. You cannot only scale storage space up, not down. Step 1 On the Instance Mgmt tab page, select an RDS DB cluster, and click. The Specify Details page is displayed. Step 2 On the Specify Details page, specify the amount of storage space to which you want to scale, and click Create Now. The maximum amount of storage space is 2,000 GB, and the minimum amount of added storage space is 10 GB. The storage space you specify must be a multiple of 10 GB. The scaling service will incur certain cost. Step 3 Check specifications on the Confirm Specifications page. Issue 05 ( ) 23

29 3 DB Instance Lifecycle Management Scaling Up a DB Instance If the information is correct, click Submit. The scaling status is displayed on the Instance Mgmt tab page. Wait for a few minutes, click in the DB instance list to expand instance information, and view the storage space to check whether the instance has been scaled up successfully. To change specifications, click Back to go back to the Specify Details page. ----End Step 1 Step 2 On the Instance Mgmt tab page, select an RDS DB instance, find the primary DB instance or read replica to be scaled, and choose More > Scale RDS in the Operation column. On the Specify Details page, click the Storage Space tab, set the value of Expanded To, and click Apply. The maximum amount of storage space is 2,000 GB, and the minimum amount of storage space is 10 GB. The storage space you specify must be a multiple of 10 GB. The scaling service will incur certain cost. Step 3 Check specifications on the Confirm Specifications page. If you do not need to modify your settings, click Submit to submit the scale-up application. The scaling status is displayed on the Instance Mgmt tab page. Wait for a few minutes, click in the DB instance list to expand instance information, and view the storage space to check whether the instance has been scaled up successfully. To change specifications, click Back to go back to the Specify Details page. Scaling up a read replica and scaling up a primary DB instance do not affect each other. The storage space of the read replica cannot exceed that of its primary DB instance. ----End 3.5 Modifying the DB Instance Class Modify the DB instance class based on service requirements. Procedure If you are changing the CPU/memory of a DB instance in a DB cluster, the DB instance cannot be deleted. Step 1 Step 2 On the Instance Mgmt tab page, select an RDS DB cluster, find the primary DB instance or read replica whose instance class is to be changed, and choose More > Scale RDS in the Operation column. On the Specify Details page, the CPU/Memory tab is displayed by default. In the Change To drop-down list, select the required specifications, and click Apply. You can choose to scale up or down. Issue 05 ( ) 24

30 3 DB Instance Lifecycle Management After the CPU/memory is changed, RDS will be restarted. Step 3 Step 4 Check specifications on the Confirm Specifications page. If you do not need to modify your settings, click Submit to submit the modification application. To change specifications, click Back to go back to the Specify Details page. View the instance specification modification result. The modification status is displayed on the Instance Mgmt tab page. Wait for a few minutes, click in the DB instance list to expand instance information, and check whether the instance specification has been modified. This process may take several minutes. ----End 3.6 Rebooting a DB Cluster or a DB Instance The RDS allows you to reboot a DB cluster or a DB instance (primary DB instance or read replica) in a DB cluster. If the RDS DB instance status is Faulty, you can try rebooting the DB cluster to restore its status to Available. When you reboot the RDS DB cluster, the service of this DB cluster is suspended. Exercise caution when deciding to perform this operation. If you reboot the DB cluster, all DB instances in the DB cluster are rebooted. After you modify certain configuration parameters, you need to reboot a DB instance for the modifications to take effect. You can reboot primary DB instances and read replicas on the console. Rebooting a DB Cluster Step 1 Select a DB cluster on the Instance Mgmt tab page, and click. Step 2 Step 3 Click OK to reboot the DB cluster. Refresh the DB instance list and view instance status. If the operation was successful, the status of all DB instances in the DB cluster is Rebooting. ----End Rebooting a DB Instance Step 1 Step 2 Step 3 On the Instance Mgmt tab page, select a DB cluster, find a primary DB instance or read replica to be rebooted in the DB instance list, and click Reboot in the Operation column. Click OK to reboot the instance. View instance status. Refresh the DB instance list. If the operation was successful, the status of the DB instance is Rebooting. ----End Issue 05 ( ) 25

31 3 DB Instance Lifecycle Management 3.7 Deleting a DB Cluster or a Read Replica You can delete unnecessary DB clusters or read replicas to release resources. After a DB cluster is deleted, all DB instances in the DB cluster are deleted as well. You are no longer charged for DB instances that have been deleted. NOTICE After you delete an RDS DB instance, all data on it, and all automated backup and snapshots related to it are deleted and cannot be restored. Exercise caution when deciding to perform this operation. Deleting a DB Cluster Step 1 Select a DB cluster on the Instance Mgmt tab page, and click. Step 2 Perform one of the following operations: If there is a snapshot in the DB cluster: If you click Yes, the latest snapshot is retained and the DB cluster is deleted. If you click No, a message is displayed, reminding you that the DB cluster cannot be restored after deletion. Click Yes to delete the DB cluster or No to cancel the deletion. If there is not a snapshot in the DB cluster: If you click Yes, the latest snapshot is created. Creating the snapshot incurs certain cost. If you click No, a message is displayed reminding you that the DB cluster cannot be restored after deletion. Click Yes to delete the DB cluster or No to cancel the deletion. ----End Deleting a Read Replica Step 1 Step 2 Choose More > Delete in the Operation column of a read replica. Click OK. Wait for a few minutes, and refresh the Instance Mgmt tab page and check whether the read replica is deleted. If the read replica is deleted, all resources and data related to the read replica will be deleted. ----End Issue 05 ( ) 26

32 4 Monitoring RDS 4 Monitoring RDS 4.1 Monitoring Resources Through CES This section describes how to monitor the system running status using the CES resource monitoring function. By monitoring system resource usage when the database is running, you can identify the period in which system resource usage is the highest. You can analyze SQL statements that may have performance issues in slow query logs of the MySQL database and in recent logs of the PostgreSQL database, allowing you to optimize the database performance. You can configure resource alarm rules on the CES console. For details, see "Alarm Rule Management" in Cloud Eye. Procedure Step 1 Step 2 Select a DB cluster on the Instance Mgmt tab page. In the displayed DB Instance List area, click More > Monitoring Information in the Operation column of an RDS DB instance of this DB cluster. The CES page is displayed. View monitoring information on the CES page. CES supports multiple monitoring time windows for performance metrics: Last 1 hour, last 3 hours, last 12 hours, last 24 hours, last 7 days, and last 30 days. DB instance monitoring metrics include ECS performance metrics and DB performance metrics. For details on ECS performance metrics, see Table 4-1. Table 4-1 ECS performance metrics Metrics Meaning Value Range CPU Usage Measures CPU usage of a measured object. 0%-100% Issue 05 ( ) 27

33 4 Monitoring RDS Metrics Meaning Value Range Memory Usage IOPS Network Input Throughput Network Output Throughput Measures memory usage of a measured object. Measures the average number of I/O requests processed by the system during a specified period. Measures the number of incoming bytes per second. Measures the number of outgoing bytes per second. 0%-100% 0 counts 0 bytes/s 0 bytes/s Disk Usage Measures disk usage of a measured object. 0%-100% DB performance metrics: For details on MySQL database performance metrics, see 5.6 Monitoring Metrics. For details on PostgreSQL database performance metrics, see 6.6 Monitoring Metrics. ----End 4.2 Viewing Logs You can view database logs through the RDS console or APIs. This section describes how to view database logs through the RDS console. For details on how to view logs through APIs, see Relational Database Service API Reference. For details on viewing MySQL logs, see 5.7 Viewing Logs. For details on viewing PostgreSQL logs, see 6.7 Viewing Recent Logs. Issue 05 ( ) 28

34 5 RDS MySQL 5 RDS MySQL 5.1 Configuring Database Security Setting Required Password Strength for Database Accounts For details on the database password strength on the RDS console, see Table 2-3. The RDS DB instance database uses comprehensive password security policies. The passwords of RDS DB instance database accounts must meet the following requirements: Contains at least eight characters. Contains at least one uppercase letter, one lowercase letter, one digit, and one special character. When you create DB instances, your password strength is checked. You can modify password strength as user root. To ensure security, you are advised to make the modified password at least as strong as the preconfigured one. 5.2 Setting Configuration Parameters Procedure To ensure optimal RDS performance, modify the configuration parameters for an RDS DB instance based on service requirements. Step 1 On the Instance Mgmt tab page, select a DB cluster and a DB instance in its DB instance list. In the Operation column of the selected DB instance, click Manage. Click the Configuration tab to go to the configuration page. Issue 05 ( ) 29

35 5 RDS MySQL For details on parameter descriptions, see the MySQL official website refman/5.6/en/server-system-variables.html. For details on parameters you can modify, see What Parameters Can I Modify on the RDS Console (MySQL)? The values of innodb_buffer_pool_size, innodb_log_file_size, innodb_spin_wait_delay, query_alloc_block_size, and thread_stack are determined by the DB instance specifications. If they are set to greater values, the database performance may be affected. key_buffer_size cannot be set to a value less than It you attempt to do so, the parameter modification fails. If max_seeks_for_key is set to a small value, database operations, such as SELECT and SHOW GLOBAL VARIABLES, are affected. If max_connections is set to a small value, database access is affected. If max_join_size is set to a small value, the database is unavailable. If sql_select_limit is set to a small value, the database query function may be unavailable. Step 2 Modify related parameters as needed, and click Save to save your changes. Click Cancel Changes to cancel your changes. Click Restore to Default to restore the default configuration. ----End After you modify certain configuration parameters for an RDS DB instance, you may need to reboot the DB instance for the modifications to take effect. If you click Restart Now, related DB instances are automatically rebooted immediately. If you click Restart Later, you need to manually reboot the DB cluster later. 5.3 Migrating Data Preparing for Data Migration Before migrating an existing MySQL database to RDS, you need to create an ECS and install the mysqldump tool. Procedure For details on how to install the MySQL client, see How Can I Install the MySQL Client? Step 1 Log in to the ECS console, and create an ECS. For details on how to create an ECS, see "Creating an ECS" in Elastic Cloud Server User Guide. The ECS is used for connecting to an RDS DB instance, and must be located in the VPC which the RDS DB instance belongs to. Configure a proper security group, allowing the ECS to access the RDS DB instance through Connection Address. Ensure the mysql tool (MySQL database client) is installed on the ECS. Step 2 Prepare a machine that can access the existing MySQL database, and install the mysqldump tool on the machine. Issue 05 ( ) 30

36 5 RDS MySQL The MySQL database or client provides this tool. ----End Exporting Data Procedure Install the version of the mysqldump tool that is the same as the MySQL database. The machine needs to be able to access existing MySQL databases. Before migrating an existing MySQL database to RDS, you need to dump the MySQL database. Step 1 Log in to the machine created in Step 2. Step 2 Use the mysqldump tool to dump the source database into an SQL file. mysqldump --databases <DB_NAME> --single-transaction --order-by-primary --setgtid-purged=off -r <BACKUP_FILE> -u <DB_USER> -p -h <DB_ADDRESS> -P <DB_PORT> DB_NAME indicates the name of the database to be migrated. BACKUP_FILE indicates the name of the file to be dumped. DB_USER indicates the database user. DB_ADDRESS indicates the database address. DB_PORT indicates the database port. Enter the password for the database when prompted: The example is as follows: [rds@localhost ~]$ mysqldump --databases my_db --single-transaction --order-byprimary --set-gtid-purged=off -r backup.sql -u root -p -h P 3306 Enter password: If you use mysqldump versions earlier than 5.6, remove --set-gtid-purged=off before running the command. After the commands are executed, the backup.sql file is generated as follows: [rds@localhost ~]$ ll backup.sql -rw-r rds rds 2714 Sep 21 08:23 backup.sql Step 3 Compress the exported SQL file. gzip backup.sql Compressing the file facilitates transmission. The backup.sql.gz file is generated upon the compression. ----End Importing Data Import the dump file to the RDS DB instance through the ECS. Issue 05 ( ) 31

37 5 RDS MySQL Procedure Step 1 Log in to the ECS created in Step 1. Step 2 Upload the backup.sql.gz package to the ECS. Select the upload method suitable for the platform you use. For example, you can run the following command in the Linux OS: scp -i <IDENTITY_FILE> <REMOTE_USER>@<REMOTE_ADDRESS>:<REMOTE_DIR>/ backup.sql.gz./ IDENTITY_FILE is the key file of the OS user on the machine where the backup.sql.gz package is stored. Upload the key file to the ECS and set its permission to 600. REMOTE_USER indicates the OS user on the machine where the backup.sql.gz package is stored. REMOTE_ADDRESS indicates the address of the machine where the backup.sql.gz package is stored. REMOTE_DIR indicates the directory of the backup.sql.gz package on the remote server. On the Windows platform, upload the backup.sql.gz package to the ECS using the winscp, xftp, or another tool. Step 3 Step 4 Decompress the package. gzip backup.sql.gz -d Import the dump file into RDS. Use the mysql tool to connect to the RDS DB instance, enter the password, and run the following commands to import the file: # mysql -h <RDS_ADDRESS> -P u root -p mysql> source <BACKUP_DIR>/backup.sql RDS_ADDRESS indicates the IP address of the RDS DB instance. BACKUP_DIR indicates the directory where the backup.sql package is located. The example is as follows: [root@ecs-zyc ~]# mysql -h P u root -p Enter password: mysql> source backup.sql Step 5 View the migration result. mysql> show databases; In this example, the database named my_db has been imported: mysql> show databases; Database information_schema my_db mysql performance_schema rows in set (0.00 sec) ----End Issue 05 ( ) 32

38 5 RDS MySQL 5.4 Restoring a DB Instance to a Specified Time Point If you enable the automated backup policy for a DB instance, you can use backup data to restore DB instance data. The restored data is the same as the backup data. Procedure Step 1 On the Instance Mgmt tab page, click a DB cluster, and select the primary DB instance in its DB instance list. In the Operation column of the selected DB instance, click Manage. Click the Backup & Restore tab, and click Restore to Specified Time Point. Only DB instances with Automated Backup enabled can be restored to the specified time point. For details on the backup policy, see Enabling the Automated Backup Policy. Step 2 Select a time range for restoration. Click to select or enter a time point within the time range, and click OK. Select where you want to restore data to, and click OK. If you choose to restore data to the current DB instance, the DB instance will be unavailable and its data will not be backed up during restoration. After data is restored, a new restoration time range is available. Between this new time range and the previous time range, there is a time gap, which is the restoration duration. Restoring to a new DB instance Go to the Specify Details page of Restore to New DB Instance to create a DB cluster using the backup data. The DB engine, version, password, and storage space of the restored DB cluster are the same as the original DB cluster, and cannot be modified. Other parameters are the same as that of the original DB cluster by default, and can be modified. If the automated backup policy is enabled, a full backup is performed after the DB cluster is created. Restoring to the current DB instance ----End 5.5 Restoring a Snapshot Check the DB instance status on the Instance Mgmt tab page. The status of the DB instance is Restoring. After you choose to restore data to the current DB instance, existing data is overwritten and the DB instance is unavailable. If the automated backup policy is enabled, a full backup is performed after the DB cluster is restored. You can use a snapshot to restore DB instance data to the time point when the snapshot was created. You can restore data to the current instance or a new one. Issue 05 ( ) 33

39 5 RDS MySQL Procedure Step 1 On the Snapshot Mgmt tab page, click the snapshot to be used for restoration, and click Restore. Perform the following operations based on whether the DB cluster which the snapshot belongs to exists. If the DB cluster exists, go to Step 2. If the DB cluster does not exist, go to Step 3. Step 2 Select the restoration method and click OK. Restore to a new instance. Go to the Specify Details page of Restore to New DB Instance to create a DB cluster using the snapshot data. The DB engine, version, password, and storage space of the restored DB cluster are the same as the original DB cluster, and cannot be modified. Other settings are the same as those of the original DB cluster by default, and can be modified. Restore to the current instance. On the Instance Mgmt tab page, the status of all DB instances in a DB cluster is Restoring. If the automated backup policy is enabled, a full backup is performed after the DB cluster is created or restored. No further operations are required. Step 3 Restore data to a new DB instance. Go to the Specify Details page of Restore to New DB Instance to create a DB cluster using the snapshot data. The DB engine, version, password, and storage space of the restored DB cluster are the same as the original DB cluster, and cannot be modified. You need to configure other settings. For details, see Creating RDS MySQL DB Instances. If the automated backup policy is enabled, a full backup is performed after the DB cluster is created. ----End 5.6 Monitoring Metrics For details on ECS performance metrics, see Table 4-1. For details on database performance monitoring metrics, see Table 5-1. Issue 05 ( ) 34

40 5 RDS MySQL Table 5-1 Database performance monitoring metrics list Metrics Meaning Value Range Total Connections Active Connections QPS TPS Buffer Pool Usage Buffer Pool Hit Rate Buffer Pool Dirty Block Rate InnoDB Read Throughput InnoDB Write Throughput File Read Speed File Write Speed Log Write Request Speed Log Physical Write Speed Log fsync() Write Speed Temporary Tables Qty Measures the total number of connection attempts to the MySQL server. Measures the number of active connections. Measures the number of SQL statement queries (including the storage process) per second. Measures the number of transaction executions (including transaction submitting and rollback) per second. Measures the ratio of dirty data to all data in the InnoDB buffer. Measures the ratio of read hits to read requests in the InnoDB buffer. Measures the ratio of used pages to total data in the InnoDB buffer. Measures the average number of read bytes per second for the InnoDB buffer. Measures the number of write bytes per second for the InnoDB buffer. Measures the average number of times that InnoDB reads files per second. Measures the average number of times that InnoDB writes to files per second. Measures the average number of log write requests per second. Measures the average number of physical writes for log files per second. Measures the average number of fsync() write requests on log files per second. Measures the number of temporary tables automatically created on hard disks when MySQL statements are executed. 0 counts 0 counts 0 queries/s 0 transactions/s 0%-100% 0%-100% 0%-100% 0 bytes/s 0 bytes/s 0 counts/s 0 counts/s 0 counts/s 0 counts/s 0 counts/s 0 tables Key Buffer Usage Measures the MyISAM key buffer usage. 0%-100% Key Buffer Write Hit Rate Measures MyISAM Key buffer write hit ratio of monitored objects. 0%-100% Issue 05 ( ) 35

41 5 RDS MySQL Metrics Meaning Value Range Key Buffer Read Hit Rate MyISAM Disk Write Speed MyISAM Disk Read Speed MyISAM Buffer Pool Write Speed MyISAM Buffer Pool Read Speed Delete Execute Speed Insert Execute Speed Insert_Select Execute Speed Replace Execute Speed Replace_Selectio n Execute Speed Select Execute Speed Update Execute Speed Row Delete Speed Row Insert Speed Row Read Speed Row Update Speed Measures MyISAM Key buffer read hit ratio of monitored objects. Measures the number of times that indexes are written into disks per second. Measures the number of times that indexes are read from disks per second. Measures the number of requests on writing indexes into the MyISAM buffer pool per second. Measures the number of times that indexes are read from the MyISAM buffer pool per second. Measures the average number of Delete statement executions per second. Measures the average number of Insert statement executions per second. Measures the average number of Insert_Select statement executions per second. Measures the average number of Replace statement executions per second. Measures the average number of Replace_Selection statement executions per second. Measures the average number of Select statement executions per second. Measures the average number of Update statement executions per second. Measures the average number of rows that are deleted from the InnoDB table per second. Measures the average number of rows that are inserted into the InnoDB table per second. Measures the average number of rows that are read from the InnoDB table per second. Measures the number of updated rows in the InnoDB table per second. 0%-100% 0 counts/s 0 counts/s 0 counts/s 0 counts/s 0 queries/s 0 queries/s 0 queries/s 0 queries/s 0 queries/s 0 queries/s 0 queries/s 0 rows/s 0 rows/s 0 rows/s 0 rows/s Issue 05 ( ) 36

42 5 RDS MySQL 5.7 Viewing Logs The RDS log management function allows you to view database-level logs, including error logs and slow query logs Viewing Error Logs Procedure This section describes how to locate database problems using error logs. Error logs include warning- and error-level logs generated when the database is running. Step 1 Step 2 On the Instance Mgmt tab page, select a DB cluster and a DB instance in its DB instance list. In the Operation column of the selected DB instance, click Manage. Then, click the Error Log tab. Viewing error log details. You can view error log records in different time periods. If error description in a log is not completely displayed, move the cursor over the Error Statement column of the log to view details. If the number of logs exceeds the specified number that can be displayed on one page, the logs are displayed on multiple pages. ----End Viewing Slow Query Logs Procedure Slow query logs record statements whose execution time exceeds the value of long_query_time (10 seconds by default). You can identify slowly executed statements based on the slow query logs and make optimization accordingly. Step 1 Step 2 On the Instance Mgmt tab page, select a DB cluster and a DB instance in its DB instance list. In the Operation column of the selected DB instance, click Manage. Then, click the Slow Query Log tab. View log details. You can query the following ranking. Top 10 Top 20 Top 50 You can rank logs by the following statement types: ALL SELECT INSERT UPDATE DELETE Issue 05 ( ) 37

43 5 RDS MySQL CREATE If description in a slow query log is not completely displayed, move the cursor over the Execute Statement column of the log to view details. ----End If you execute identical SQL statements, with different parameters, only one SQL statement is displayed as an example in a slow query log. For example, if two select sleep(n) statements (select sleep(11) and select sleep(12)) are executed, only select sleep(11) is displayed in the slow query log result. Issue 05 ( ) 38

44 6 RDS PostgreSQL 6 RDS PostgreSQL 6.1 Configuring Database Security Password Strength Requirements For details on the database password strength on the RDS console, see Table 2-8. The RDS DB instance database uses comprehensive password security policies. The passwords of RDS DB instance database accounts must meet the following requirements: Contains at least eight characters. Contains digits and characters. Is different from the user name. Suggestions for Creating Users When you run CREATE USER or CREATE ROLE, you are advised to specify the VALID UNTIL 'timestamp' parameter (timestamp indicates the expiration timestamp) to set the password expiration period. 6.2 Setting Configuration Parameters Procedure To ensure optimal RDS performance, modify the configuration parameters for an RDS DB instance based on service requirements. Step 1 On the Instance Mgmt tab page, select a DB cluster and a DB instance in its DB instance list. In the Operation column of the selected DB instance, click Manage. Click the Configuration tab to go to the configuration page. Issue 05 ( ) 39

45 6 RDS PostgreSQL For details on parameter descriptions, see the PostgreSQL official site docs/current/static/runtime-config.html. For details on parameters you can modify, see What Parameters Can I Modify on the Console (PostgreSQL)? If log_statement is set to ddl, mod, or all, the operations of creating and deleting database users, including passwords and other sensitive information, are recorded. Database performance is also affected. Execution caution when deciding to set this parameter to ddl, mod, or all. search_path must be set to a schema sequence where schemas are separated by commas (,). Ensure that the schemas exist. Otherwise, the database performance is affected. Enabling the following parameters will affect the database performance: log_hostname, log_duration, log_connections, and log_disconnections. Exercise caution when deciding to enable these parameters. If you enable the parameter log_duration, SQL statements containing sensitive information may be recorded in logs. You are advised to disable this parameter. If the parameter log_min_duration_statement is set to 0, SQL statements containing sensitive information will be recorded in logs. You are advised to disable this parameter (setting it to -1). Step 2 Modify related parameters as needed, and click Save to save your changes. Click Cancel Changes to cancel your changes. Click Restore to Default to restore the default configuration. ----End After you modify certain configuration parameters for an RDS DB instance, you may need to reboot the DB instance for the modifications to take effect. If you click Restart Now, related DB instances are automatically rebooted immediately. If you click Restart Later, you need to manually reboot the DB cluster later. 6.3 Migrating Data Preparing for Data Migration Before migrating an existing PostgreSQL database to RDS, you need to create an ECS and install the pg_dump tool. Procedure For details on how to install the PostgreSQL client, see How Can I Install the PostgreSQL Client? Step 1 Log in to the ECS console, and create an ECS. For details on how to create an ECS, see "Creating an ECS" in Elastic Cloud Server User Guide. The ECS is used for connecting to an RDS DB instance, and must be located in the VPC which the RDS DB instance belongs to. Configure a proper security group, allowing the ECS to access the RDS DB instance through Connection Address. Ensure the psql tool (PostgreSQL database client) is installed on the ECS. Issue 05 ( ) 40

46 6 RDS PostgreSQL Step 2 Prepare a machine that can access the existing PostgreSQL database, and install the pg_dump tool on the machine. The PostgreSQL database or client provides this tool. ----End Exporting Data Procedure Install the version of the pg_dump tool that is the same as the PostgreSQL database. The machine needs to be able to access existing PostgreSQL databases. Before migrating the PostgreSQL database to RDS, you need to dump the PostgreSQL database. Step 1 Log in to the machine created in Step 2. Step 2 Use the pg_dump tool to dump the source database into an SQL file. pg_dump --username=<db_user> --host=<db_address> --port=<db_port> --format=plain --file=<backup_file> <DB_NAME> DB_USER indicates the database user. DB_ADDRESS indicates the database address. DB_PORT indicates the database port. BACKUP_FILE indicates the name of the file to be dumped. DB_NAME indicates the name of the database to be migrated. Enter the password for the database when prompted: The example is as follows: [rds@localhost ~]$ pg_dump --username=root --host= port= format=plain --file=backup.sql my_db Password for user root: After the commands are executed, the backup.sql file is generated as follows: [rds@localhost ~]$ ll backup.sql -rw-r rds rds 2714 Sep 21 08:23 backup.sql Step 3 Compress the exported SQL file. gzip backup.sql Compressing the file facilitates transmission. The backup.sql.gz file is generated upon the compression. ----End Importing Data Import the dump file to the RDS DB instance through the ECS. Issue 05 ( ) 41

47 6 RDS PostgreSQL Procedure Step 1 Log in to the ECS created in Step 1. Step 2 Upload the backup.sql.gz file to the ECS and decompress it. Select the upload method suitable for the platform you use. For example, you can run the following command in the Linux OS: scp -i <IDENTITY_FILE> <REMOTE_USER>@<REMOTE_ADDRESS>:<REMOTE_DIR>/ backup.sql.gz./ IDENTITY_FILE indicates the key file of the OS user on the machine where the backup.sql.gz file is stored. Upload the key file to the ECS and set its permission to 600. REMOTE_USER indicates the OS user on the machine where the backup.sql.gz package is stored. REMOTE_ADDRESS indicates the address of the machine where the backup.sql.gz file is stored. REMOTE_DIR indicates the directory of the backup.sql.gz file on the remote server. On the Windows platform, upload the backup.sql.gz file to the ECS using the winscp, xftp, or another tool. Step 3 Step 4 Decompress the package. gzip backup.sql.gz -d Import the dump file into RDS. Use the psql tool to connect to the RDS DB instance, and run the following commands to import the file: # psql --host=<rds_address> --port= username=root --dbname=<db_name> -- file=<backup_dir>/backup.sql RDS_ADDRESS indicates the IP address of the RDS DB instance. DB_NAME indicates the name of the database to be imported. Ensure that the database exists. BACKUP_DIR indicates the directory where the backup.sql file is located. Enter the password for the RDS DB instance when prompted. The example is as follows: [root@ecs-zyc ~]# psql --host= port= username=root -- dbname=my_db --file=backup.sql Password for user root: Step 5 View the migration result. my_db=> \l my_db In this example, the database named my_db has been imported: my_db=> \l my_db List of databases Name Owner Encoding Collate Ctype Access privileges my_db root UTF8 en_us.utf-8 en_us.utf-8 (1 row) ----End Issue 05 ( ) 42

48 6 RDS PostgreSQL 6.4 Restoring a DB Instance to a Specified Time Point Procedure If you enable the automated backup policy for a DB instance, you can use backup data to restore DB instance data. The restored data is the same as the backup data. Step 1 On the Instance Mgmt tab page, click a DB cluster, and select the primary DB instance in its DB instance list. In the Operation column of the selected DB instance, click Manage. Click the Backup & Restore tab, and click Restore to Specified Time Point. Only DB instances with Automated Backup enabled can be restored to the specified time point. For details on the backup policy, see Enabling the Automated Backup Policy. Step 2 Select a time range for restoration. Click to select or enter a time point within the time range, and click OK to go to the Specify Details page of Restore to New DB Instance. Create a DB cluster using the backup data. The DB engine, version, password, and storage space of the restored DB cluster are the same as the original DB cluster, and cannot be modified. Other parameters are the same as that of the original DB cluster by default, and can be modified. If the automated backup policy is enabled, a full backup is performed after the DB cluster is created. ----End 6.5 Restoring a Snapshot Procedure You can use a snapshot to restore DB instance data to the time point when the snapshot was created. Step 1 Step 2 On the Snapshot Mgmt tab page, click the snapshot to be used for restoration, and click Restore. On the Specify Details page of Restore to New DB Instance, create a DB cluster using the snapshot data. The DB engine, version, password, and storage space of the restored DB cluster are the same as the original DB cluster, and cannot be modified. If the DB cluster that the snapshot belongs to exists, other settings are the same as those of the original DB cluster by default, and can be modified. If the DB cluster which the snapshot belongs to does not exist, you need to configure other settings. For details, see Creating RDS PostgreSQL DB Instances. If the automated backup policy is enabled, a full backup is performed after the DB cluster is created. ----End Issue 05 ( ) 43

49 6 RDS PostgreSQL 6.6 Monitoring Metrics For details on ECS performance monitoring metrics, see Table 4-1. For details on database performance monitoring metrics, see Table 6-1. Table 6-1 Database performance metrics list Metrics Meaning Value Range Transaction logs usage Replication slot usage Database connections Maximum used transaction ids Transaction logs generations Oldest replication slot lag Measures the disk capacity used by transaction logs. Measures the disk capacity used by replication slot files. Measures the number of database connections in use. Measures the maximum transaction ID that has been used. Measures the size of transaction logs generated per second. Measures the lag of the most laggy replica in terms of WAL (write-ahead log) data received. 0 MB 0 MB 0 counts 0 counts 0 MB/s 0 MB Replication lag Measures replication lag. 0 ms 6.7 Viewing Recent Logs Procedure This section describes how to locate database problems using recent logs generated when the database is running. Step 1 On the Instance Mgmt tab page, select a DB cluster and a DB instance in its DB instance list. In the Operation column of the selected DB instance, click Manage. Then, click the Recent Logs tab to view the log file list stored in the database. The log file list includes the following: Name Last Record Time Size Log files are sorted by last record time by default and can be displayed on multiple pages. A number of 10 logs are displayed on each page by default. You can set the number of logs displayed on a page to 10, 20, or 50. You can enter a log file name in the search box in the upper-right corner to query information of the log file. Issue 05 ( ) 44

50 6 RDS PostgreSQL The log file list is generated by hour or day (determined by log_filename) and can be stored in the database for a maximum of 30 days. When the size of log files exceeds 1 GB, the system will automatically clear the oldest log files until the total size of log files is no greater than 800 MB. Step 2 Click View to view the details of the selected log file. Logs are classified into the following levels: DEBUG (1-5) INFO NOTICE WARNING ERROR LOG FATAL PANIC You can set the parameter log_min_messages to prevent messages that exceed the specified log level from being written to the server logs. On the log information page, the first 1000 lines of the log file are displayed. You can click Refresh to load the next 1000 lines of the log file until the file is completely loaded. If the total size of the 1000 lines to be loaded exceeds 1 MB, all lines after the 1 MB limit is met are not loaded. For example, if the size of the log exceeds 1 MB when the system is loading line 801, only 800 lines of the log are loaded. ----End Issue 05 ( ) 45

51 7 FAQs 7 FAQs 7.1 Common FAQs What Precautions Should Be Taken When Using RDS? 1. RDS failover The RDS uses the HA mode to implement the failover. If the primary instance is faulty, the RDS is switched over to the standby instance in a few minutes. Databases cannot be accessed during failover. You must set automatic reconnections between the applications and RDS to prevent the applications from becoming unavailable due to the failover. 2. The operating system (OS) for DB instances is invisible to you. Your applications can only access the IP addresses and ports corresponding to the database. 3. ECSs used for RDS and backup files stored on the OBS are invisible to you. They are only visible in the RDS backend management system. 4. Precautions after purchasing an RDS DB instance: After purchasing the RDS DB instance, you do not need to perform basic database O&M operations, such as HA and security patches. Pay attention to: a. Whether the CPU, input/output operations per second (IOPS), and space for the RDS DB instances are sufficient. If any of them is insufficient, change the CPU/ memory or scale up the DB instance. b. Whether the performance of the RDS DB instance is satisfying, whether a large number of slow query SQL statements exist, whether SQL statements need to be optimized, and whether any index is redundant or missing What Is the Availability of RDS DB Instances? Formula for an RDS DB instance availability: Availability of RDS DB instances = 1 (Failure duration/total service duration) x 100% Can I Use a Template to Create RDS DB Instances? Currently, you cannot use a template to create RDS DB instances. You can raise a requirement if you want to create RDS DB instances using a template. Issue 05 ( ) 46

52 7 FAQs What Are the Differences Between RDS and Other Database Solutions? Table 7-1 Differences between RDS and other database solutions Function RDS Database Service Deployed on a Self- Purchased Server Service availability For details, see ECS. Requires self-assurance, self-setup of a primary/ standby environment, and self-setup of RAID. Data reliability System security Database backup Hardware and software investment For details, see Elastic Volume Service (EVS). Anti-Distributed denial of service (DDoS) attack is supported, helping you repair various database security vulnerabilities in a timely manner. Data is automatically backed up. No requirement. Payment depends on your demand. Requires self-assurance, self-setup of a primary/ standby environment, and self-setup of RAID. You must deploy a system security solution by yourself, which is costly, and repair database security vulnerabilities by yourself. You must find backup storage space to back up the database by yourself and periodically check whether backup data can be restored. The database server cost is high. System hosting No hosting cost is required. The hosting cost is high. Maintenance cost O&M is not required. Full-time Database Administrators (DBAs) are required for maintenance, leading to high manpower costs. Deployment and scaling Resource utilization You can use RDS after purchasing it. It is quickly deployed, is used based on your requirements, and supports flexible scaling. The expense is settled based on the actual situation, implementing high resource usage. Preparations, such as hardware purchase, equipment root hosting, and machine deployment, are required and timeconsuming. Peak resource usage is considered, leading to low resource usage. Issue 05 ( ) 47

53 7 FAQs Will My RDS DB Instances Be Affected by Other Users' RDS DB Instances? No. Your RDS DB instances are isolated from other users' RDS DB instances. Resources are also isolated How Many RDS DB Instances Can RDS Run? By default, RDS allows each tenant to have a maximum of 20 RDS DB instances. If your applications require more RDS DB instances, tell the customer manager or customer support about your requirements to apply for more RDS DB instances How Many Databases Can Run in an RDS DB Instance? The maximum number of MySQL and PostgreSQL databases that can run in an RDS DB instance depends on the database engine settings. The MySQL allows you to create a maximum of 1,000 databases and 1,000 database accounts. The PostgreSQL allows you to create unlimited numbers of databases and database accounts. 7.2 Management FAQs What Can I Do About Websites Becoming Slower to Respond after Using RDS? To solve this problem, you are advised to perform the following operations: Check the performance status of RDS DB instances on the RDS console. This problem may also be related to applications. Check and compare the current database connection status of the local database and the RDS DB instance What Should I Do If My Query Is Slow? You can check whether any slowly executed SQL queries exist, and view performance characteristics of queries (if any) to locate the cause of slow query execution. For details on viewing MySQL logs, see Viewing Slow Query Logs. For details on viewing PostgreSQL logs, see 6.7 Viewing Recent Logs. You can also view CPU usage metrics of RDS DB instances to facilitate problem locating. For details, see 4.1 Monitoring Resources Through CES What Is the Time Delay Between Primary/Standby Synchronization? The delay for primary/standby synchronization cannot be calculated using a formula. The delay is affected by the following factors: Network communication status Issue 05 ( ) 48

54 7 FAQs Transaction pressure on the primary DB instance that is, transactions per second (TPS) of the primary DB instance Transaction size executed by the primary DB instance, that is, the duration of a transaction execution Load balance of the standby DB instance and read replicas If the primary DB instance bears heavy pressure within a period and executes a large number of transactions per second, the synchronization to the standby host is delayed. Generally, the delay is at the second level. Currently, no method is available to check data consistency between the primary and standby MySQL DB databases. To check data consistency between the primary and standby PostgreSQL DB instances, view Replication Lag on the CES page to obtain the delay value of primary/standby synchronization. For details, see 4.1 Monitoring Resources Through CES How Do I Identify Data Corruption? Data tampering Lots of security measures are provided to ensure that only authenticated users have permissions to perform operations on database table records. The SSH protocol is inaccessible to users. Database tables can be accessed only through the specified database service port. Transmission package verification during primary/standby synchronization can prevent data tampering. MySQL uses the InnoDB storage engine to prevent data damage. DB instance servers may be powered off suddenly, causing database page corruption and database rebooting failures. In this case, the RDS failover is triggered Why Is a Table Missing or Data Deleted from My Database? RDS does not delete or perform any operations on any user data. If this problem occurs, check whether a misoperation has been performed. If necessary, roll back the database to the backup point. Solution: Restore RDS DB instances with the backup data to the backup point. If you have backed up data, run the data migration tool on the ECS to import the data to the RDS DB instance Can Multiple ECSs Connect to the Same RDS DB Instance? Within the limits of database capability, multiple ECSs can connect to the same RDS DB instance What Happens to the RDS Database Backup After the RDS DB Instance Is Deleted? It depends on whether you agree to retain the latest snapshot. If you agree to retain the latest snapshot: If any snapshots exist, the latest snapshot is retained. Issue 05 ( ) 49

55 7 FAQs If no snapshot exists, click Yes. The Create Snapshot page is displayed. You need to create a snapshot and retain it. Retaining the snapshot incurs certain cost. If you do not agree to retain the latest snapshot, after the RDS DB instance is deleted, its automated backup and snapshot are also deleted Will My Backups Be Deleted If I Close My Cloud Account? If your cloud account is closed, your automated backups and snapshots will be deleted Are My RDS DB Instances Available During Scaling? Currently, you can modify the storage space and instance class for an RDS DB instance. During storage space scaling, RDS DB instances are available, and services are not affected. However, you cannot delete or reboot DB instances that are being scaled. During the DB instance class modification, database services are rebooted. RDS DB instances are unavailable and cannot be connected. You cannot delete the DB instance during the DB instance class modification Does RDS Support Read/Write Splitting? RDS supports read/write splitting. A maximum of five read replicas can be created for one RDS DB cluster. Currently, you cannot use the SQL Proxy for read replica IP addressing. You need to configure your applications for IP addressing to let your read replicas serve read/write requests. 7.3 Connection and Access FAQs Can an External Server Access the RDS Database? An external server cannot access the RDS database. You can access the RDS database using either of the following methods: Enable the VPN service in a VPC and use VPN to connect to the RDS database. For details about how to enable VPN, see Virtual Private Cloud. Create an ECS and an RDS database in the same VPC, and bind a public IP address to the ECS. You can access the RDS database through the ECS What Does "Number of RDS DB Connections" Mean? The number of RDS DB connections indicates the number of applications that can be simultaneously connected to the RDS DB instance. The number of RDS DB connections is irrelevant to the maximum number of users allowed by applications or websites What Should I Do If the ECS Cannot Connect to the RDS DB Instance? Perform the following steps to identify the problem: Issue 05 ( ) 50

56 7 FAQs Step 1 Step 2 Step 3 Check whether the ECS and the RDS DB instance are located in the same VPC. If they are in the same VPC, go to Step 2. If they are in different VPCs, create an ECS in the VPC where the RDS DB instance is located. Check whether a security group has been added for the ECS. If a security group has been added, check whether its configuration rules are suitable. For details, see the description of a security group in Table 2-4. Then, go to Step 3. If no security group has been added, go to the VPC page from the Elastic Cloud Server console, and click Security Groups to add a security group. On the ECS, check whether the port of the RDS DB instance can be connected to. The default port number of the MySQL and PostgreSQL is telnet <connection address> {8635} If the connection is normal, the network between the ECS and the RDS DB instance is normal. If the port cannot be connected to, contact post-sales technical support for troubleshooting. ----End What Should I Do If a Database Client Problem Causes a Connection Failure? Identify an RDS connection failure caused by incorrect client configuration from the following aspects: If the fault persists, contact post-sales technical support. ECS Security Policy In Windows, check whether the RDS DB instance port is enabled in the Windows security policy. In Linux, run the iptables command to check whether the RDS DB instance port is opened in firewall settings. Application Configuration Check whether the connection address, port parameter configuration, and JDBC connection parameter configuration are correct. Incorrect User Name or Password Check whether the user name or password is correct if an error similar to the following occurs during RDS DB connection: [Warning] Access denied for user 'username'@'yourip' (using password: NO) [Warning] Access denied for user 'username'@'yourip' (using password: YES) Issue 05 ( ) 51

57 7 FAQs What Should I Do If an RDS DB Instance Problem Causes a Connection Failure? Check whether the following problems occur on the RDS DB instance. Check the following one at a time. 1. The RDS DB instance is not properly connected to. Solution: Check the connection mode. The RDS can be accessed only through an ECS in the same VPC. 2. The maximum number of connections is reached. Solution: Check whether the number of current connections and the CPU usage are normal by using the RDS resource monitoring function. If the number of connections reaches the maximum, reboot the RDS DB instance, disconnect from the RDS DB instance, or modify the RDS DB instance class. 3. The RDS DB instance is abnormal. For example, the RDS DB instance reboot fails, RDS becomes faulty, or the RDS DB instance or table is locked. Solution: Reboot the RDS DB instance to see if the problem is resolved. If the fault persists, contact post-sales technical support How Can My Applications Access an RDS DB Instance in a VPC? Ensure the ECS where your applications are located is in the same VPC and subnet as the RDS DB instance is. If the ECS and the RDS DB instance are in different subnet or VPCs, modify the VPC route table and network access control list (ACL) to ensure the ECS can access the RDS DB instance Do Applications Need to Support Automatic Reconnection to the RDS DB Instance? You are advised to set your applications to support automatic reconnection to the RDS DB instance, increasing availability. After the reboot or failover of an RDS DB instance, the applications automatically reconnect to the RDS DB instance. In addition, you are advised to set your applications to connect to the RDS DB instance using a long connection. Short connections affect performance and consume resources What Types of DB Engines Does RDS Support for Importing? Exporting and importing data between DB engines of the same type is called homogeneous database export and import. Exporting data from Oracle or SQL Server to MySQL or PostgreSQL is called heterogeneous database export and import. Data cannot be exported or imported between heterogeneous databases due to different data formats. However, if the data formats are compatible, you can import table data to MySQL or PostgreSQL from Oracle or SQL Server theoretically. Generally, third-party software is required for data replication to export and import between heterogeneous databases. For example, use a third-party tool to export table Issue 05 ( ) 52

58 7 FAQs records from Oracle or SQL server in.txt format and then use Load statements to import the exported table records to MySQL or PostgreSQL Why Do I Need to Use the mysqldump or pg_dump Tool for Migration? The mysqldump or pg_dump tool is easy to use for data migration. However, when you use this tool, the server is stopped for a long period of time during data migration. Therefore, use this tool when the data amount is small or the server is allowed to stop for a long period of time, during which the data can be migrated. RDS is completely compatible with original database services. For you, the procedure for migrating data from a primitive database to RDS is similar to the procedure for migrating data from a database server to another one How Can I Install the MySQL Client? Procedure MySQL provides client installation packages for different OSs at its official website. To obtain the version 5.6 of MySQL client installation package, visit downloads/mysql/5.6.html#downloads. To obtain other versions of the MySQL client installation packages, visit This following uses Red Hat Linux OS as an example to describe how to obtain the required installation package and install the MySQL client. Step 1 Obtain the installation package. Find the download link for the required version on the download page. For example, to download MySQL-client el6.x86_64.rpm, go to file/?id= Figure 7-1 Downloading Click the link highlighted in the red box to download the installation package. The URL is dev.mysql.com/get/downloads/mysql-5.6/mysql-client el6.x86_64.rpm. Step 2 Upload the installation package to the ECS. Issue 05 ( ) 53

59 7 FAQs When you create an ECS, select an OS, for example, Red Hat 6.6, and bind an Elastic IP (EIP) to it. Then, upload the installation package to the ECS using a remote tool, and use PuTTY to connect to the ECS. Step 3 Run the following command to install the MySQL client: sudo rpm -ivh MySQL-client el6.x86_64.rpm ----End If any conflicts occur during the installation, add the replacefiles parameter to the command and install the client again. The example is as follows: rpm -ivh --replacefiles MySQL-client el6.x86_64.rpm How Can I Install the PostgreSQL Client? Procedure PostgreSQL provides client installation packages and required dynamic shared library packages for different OSs at its official website. To obtain the PostgreSQL 9.5 client installation package in Red Hat Linux 6, visit x86_64/repoview/postgresqldbserver95.group.html. This section uses PostgreSQL 9.5 as an example to describe how to obtain the required installation package and install the MySQL client. Step 1 Obtain the PostgreSQL client installation package. Find the download link for the required version on the download page. For example, to download postgresql95, go to repoview/postgresql95.html. Figure 7-2 Downloading the PostgreSQL client Click the link highlighted in the red box to download the installation package. The URL for the link is Step 2 Obtain the dynamic shared library package required for the PostgreSQL client. Issue 05 ( ) 54