Chapter 3 `How a Storage Policy Works

Transcription

1 Chapter 3 `How a Storage Policy Works

2 32 - How a Storage Policy Works A Storage Policy defines the lifecycle management rules for all protected data. In its most basic form, a storage policy can be thought of as a container with one or more sets of rules that define how data will be managed. These rules are called Storage Policy Copies. Within the storage policy, multiple copies can be created, each with their own set of rules. There are three essential rules that every storage policy will have: Data that will be managed. The data path to protected storage. How long it will be kept in storage. The principal concept in CommVault data management is that production data can be containerized into subclients. A subclient defines the actual data that will be protected. These subclients can contain an entire server, drive, folders, database, user mailboxes, virtual machines, or even document repositories. These subclients are protected through backup, archive, or snapshot operations into CommVault protected storage. Once in protected storage the subclients can be independently managed regardless of what production server they came from. Financial and legal data from different production systems can be combined into a storage policy copy for compliance reasons. Databases can be managed in another copy and sent to a DR location. User files can be kept in an on-site copy for quick file/folder level recovery. CommVault s concept in data management is to design a data protection strategy based on policies, transcending limitations of legacy data protection products. The flexibility gained from policy driven data protection and management is the ability to group data based on protection and retention needs, greatly simplifying the organization and management of protected data. Diagram showing subclient data copied to a storage policy with three copies. The logical subclient division of production data allows the data to be independently managed within the storage policy.

3 How a Storage Policy Works - 33 It is important to understand that a storage policy defines rules for how data will be managed. Moving the data into the storage policy and from one copy to another will be done through scheduling mechanisms such as schedule policies and auxiliary copy operations. These concepts will be covered in the Data Movement Process chapter. Logical Divisions of Business Data A storage policy creates logical boundaries for protected data. Data associated with and managed by a storage policy is bound to that policy. Protected data can be moved between copies within the same storage policy, but the data cannot be moved from one storage policy to another. This data isolation can be crucial when considering the management of data by different departments, by different data types, different retention needs, or different storage locations. Diagram showing two storage policies. The first policy manages with a DR copy and an archive copy. The second policy manages database data with an on-site and offsite DR copy.

4 34 - How a Storage Policy Works Deleting Storage Policies Since the CommVault software logically manages all protected data through storage policies it is absolutely critical to understand that if a policy is deleted, all associated data will be unrecoverable through the CommCell Console. Storage policies containing retained data should not be deleted until all data managed by the policy has aged. You can use the job history view to determine if data is still being managed by a policy. If it is, consider renaming the policy. For example: SP_Win_Servers can be renamed X_SP_Win_Serv can represent the data in which all data will be aged from the policy and at that point it can be deleted. NOTE: you can change the name of a storage policy at any time. In Simpana Version 9 you now have the ability to hide a storage policy. In the General tab of the storage policy properties the option to Hide Storage Policy can be selected. This will not only hide the policy in the storage policy list, but it will also hide the storage policy in the subclient properties so the policy cannot be accidentally selected in future configurations. The option Show hidden storage policies setting in Service Configurations in the Media Management applet in Control Panel can be set to 1 to make hidden policies visible. Storage Policy Copies The concept of Storage Policy Copies is that the data from the production environment only has to be moved to protected storage once. Once the data is in protected storage, the storage policy logically manages and maintains independent copies of the data. This allows for great flexibility when managing data based on the three key aspects of data protection: disaster recovery, data recovery, and data archiving. There are three types of storage policy copies Primary Copy Secondary Synchronous Copy Secondary Selective Copy Primary Copy A storage policy Primary Copy sets the primary rules for protected data. Each storage policy can have two primary copies, a Primary Snap copy and Primary Classic copy. A Primary Snap is used to manage protected data using the Simpana SnapProtect feature and a Primary Classic which will manage traditional agent based data protection jobs. Most rules defined during the policy creation process can be modified after it has been created. Settings that cannot be changed after the creation is whether it is a deduplicated enabled policy and whether the primary copy is associated with a global deduplication policy. For more information on Simpana Deduplication see the Deduplication chapter.

5 How a Storage Policy Works - 35 During data protection operations, performance is a major issue and meeting operation windows is becoming more difficult as data requiring protection continues to grow. Understanding how CommVault software works and optimally configuring the primary copy is crucial. Using high performance storage as the primary copy target is the best method to ensure windows are met. CommVault recommends using disk storage as a primary storage location especially with the introduction of Client side deduplication in Simpana 9. Secondary Copies Once data is protected to the primary copy location, additional copies can be created. The advantage of this architecture is that additional copies can be generated within the protected storage environment without impacting production resources. You can configure as many secondary copies as you need to manage stored data. This allows for great flexibility in meeting company policies which may sometimes be determined by people who don t necessarily understand CommVault technology. Realize that the Simpana software can be configured in an endless number of ways. It is very rare that someone proposes a scenario that cannot be accomplished with the CommVault software. Many of these scenarios will be covered in this book. There are two types of secondary copies: Secondary Synchronous Secondary Selective A secondary copy will be a synchronous copy by default. To make the copy a selective copy select the Selective Copy check box. Secondary Synchronous Copy A Synchronous Copy defines a secondary copy to synchronize protected data with a source copy. All valid data (jobs that completed successfully) written to the source copy will be copied to the synchronous copy via an update process called an Auxiliary Copy operation. This means all full, incremental, differential, transaction log, or archive job from a source copy will also be managed by the synchronous copy. Synchronous copies are useful when you want a consistent point-in-time copy for any point within the cycle of all protected data available for restore.

6 36 - How a Storage Policy Works When a synchronous copy is defined an effective start date can be set to determine the starting point for data to be copied. This is configured in the Copy Policy tab of the secondary copy. The default is All Backups which means all jobs currently in the source copy will be copied to the synchronous copy when an auxiliary job runs. Auxiliary copy jobs will be covered in the Data Movement Process chapter. You can customize this option and select an effective start date for when the synchronous copy will become active. Synchronous copies are used to meet the following requirements: Consistent point-in-time copies of data required to restore data to a particular point in time within a cycle. Copies that are required to be sent off-site daily. To provide the ability to restore multiple versions of an object from a secondary copy within a cycle. Synchronous copies create additional copies of all Full, Incremental, and Differential data protection operations. Secondary Selective Copy A Selective Copy allows automatic selection of specific full backups or manual selection of any backup for additional protection. Selective copy options allow the time based automatic selection of: all, weekly, monthly, quarterly, half-year, and/or yearly full backups. Advanced options allow you to generate selective copies based on a frequency of number of cycles, days, weeks, or months. You can also choose the Do Not Automatically Select Jobs option which allows you to use auxiliary copy schedules to determine when copies of full backups will be made.

7 How a Storage Policy Works - 37 Selective copies are used to meet the following requirements: Data being sent off-site weekly, monthly, quarterly, or yearly. Archiving point-in-time copies of data for compliance and government regulations. Example showing a selective copy configured to take the end of the month full to create an additional copy. The Essential Rules for Storage Policy Copies Selecting Subclient Data One of the more difficult concepts for backup administrators transitioning from legacy backup products to CommVault software is that a server is not directed to a storage policy, subclient data on the server is. This is done by defining what data a subclient will manage. For most file systems and applications, when an idataagent is installed, a default subclient is automatically generated. For these agents, the default subclient will protect all data the agent is responsible for. Additional subclients can be created to meet performance, management and special protection requirements. When additional subclients are created the defined data within the subclient is automatically excluded from the default subclient. This means data is mutually exclusive to a subclient and cannot be part of any other subclient within a data set. This allows for data to be containerized within a subclient which can be independently protected and managed based on protection and retention requirements.

8 38 - How a Storage Policy Works Selecting Data for Primary Copy The storage policy that will manage the subclient is defined in the Storage Device tab of the subclient properties. A subclient can only be associated with one storage policy. SQL subclients can be associated two storage policies, one for full and differential backups and one for transaction log backups. The storage policy that is defined in the subclient determines the primary copy location. To associate a subclient with a storage policy use the Storage Device tab in the subclient properties. In the Storage Policy drop down box select the storage policy to associate the subclient with. Selecting Data for Secondary Copies Determining what data will be managed by a secondary copy can be configured in the Subclient Associations tab of the secondary copy Subclients can be configured in the subclient associations in any number of combinations allowing like data to be managed by the copy. So if you wanted all data for a specific server in the secondary copy, add all subclients in the Associations tab. If you wanted all user home folders that are on four different servers within a copy, define specific subclients on each server to manage the home folders and then associate those subclients with the copy.

9 How a Storage Policy Works - 39 A storage policy with a primary and two secondary copies to accomplish data protection goals. Three subclients are associated with the storage policy and will be managed in the primary copy. Two secondary copies are created, each managing specific data. Subclients are associated with a secondary copy in the Associations tab of the policy copy. By default, all subclients will be associated with a secondary copy.

10 40 - How a Storage Policy Works Defining the Data Path The storage policy the subclient data is associated with determines the data path. The path is used to move data from the source location to protected storage. All active subclients must be associated with a storage policy. A data path if made up of four components: 1. Media Agent 2. Library 3. Drive pool 4. Scratch pool Media Agent Media Agents are the workhorses that move data from production servers to the backup environment. They supply the processing power to receive data, arrange it in chunk format, and send it to the library. Media Agents can also be responsible for encryption, compression, or deduplication processing. Library Libraries are logically defined and are categorized as stationary or removable media libraries. Stationary libraries define a path to a disk location such as a drive letter or UNC path. They are considered stationary since these paths do not change once defined. It is possible to change these paths in the Library and Drive Configuration tool in Control Panel. Disk libraries provide several advantages over tape (removable) media: Multiple streams can be written to a disk library simultaneously. It is more efficient to copy data from a disk library to a tape library when off-site removable media is required. Data deduplication can be used greatly reducing disk storage requirements and network bandwidth usage. Data stored on disk can be replicated to additional disk storage locations. Object level recovery is considerably faster from disk as opposed to tape. Removable media libraries are generally thought of as tape libraries but they can also be magnetic optical or USB storage devices. The advantage of removable media libraries is that media can be moved between libraries and recognized by Simpana software to be restored. Capacity can also be inexpensively added by simply adding more media to the library. Tape libraries also provide an advantage of having an offline copy of data which will be less susceptible to corruption or hacking. Drive Pool (Removable Media Libraries Only) Drive pools are a single Media Agent s view of allocated drives within a removable media library. Use of drive pools gives the Media Agent the flexibility of drive choice and usage within a library. Without drive pools, assigning and sending a data protection job to a specific drive will fail if the drive is broken or offline. Having a pool of drives to choose from gives the job the best chance of success. Drive pools are defined within the storage policy copy s data path which allows you to specify which drives certain storage policies can use. Although the Media Agent may be able to see all drive pools in a library, you can

11 How a Storage Policy Works - 41 specify a specific drive pool to be used by the policy copy. This can allow you to assign data to drives on a more granular level. Drive pools can be configured in the Library and Drive Configuration tool in Control Panel. There is also a Master Drive Pool configuration available within a Library. Master Drive Pools are used to separate dissimilar drive types into different drive pools. For example; a library may have four physical drives made up of two LTO4 and two LTO5 drives. While the media written to by LTO4 drives can be read in an LTO5 drive, the opposite is not true. A Master Drive Pool enables the separation of different drive types and their respective media. Scratch Pool (Removable Media Libraries Only) Scratch pools allow new and re-usable media within the library to be logically grouped based on media type and intended usage. At least one default scratch pool exists for every removable media library. Master drive pools can be assigned their own default scratch pools. Additional user-defined scratch pools can be created, assigned media manually or automatically and assigned to a storage policy copy s data path. The following diagram illustrates the use of drive pools and scratch pools to logically divide resources within a removable media library.

12 42 - How a Storage Policy Works Retention Retention is defined in the Retention tab of the storage policy copy. Each copy will have its own retention configurations. There are several types of retention that can be defined: Backup data retention is defined in Cycles and Days. Archive Retention for archiving and compliance archiving agents is defined as days. Extended retention which allows for Grandfather / Father / Son retention to be applied to full backups. The Retention chapter will cover these concepts in great detail. Additional Rules for Storage Policy Copies The following section briefly discuses additional features and rules that can be applied to a storage policy copy. These features will be discussed in different parts of the book. Feature Description GridStor Technology Allows for multiple data paths to be defined for a policy copy. Path usage can be configured to use LAN-Free paths, failover between paths in the event a path is unavailable, or to load balance between multiple paths. Data Path Properties Allows individual data paths to be customized. Custom chunk size, block size, compression options, and encryption options can be set for each data path. Data Deduplication Deduplication configurations to manage stores, set Silo options, enable DASH Full or DASH copy, configure compression, and set block retention. Off line Encryption Off line or copy based encryption will encrypt data when being copied to secondary copy locations. Different algorithms and key lengths can be configured and the location of keys set. Multiplexing Multiplexing can be configured to multiplex source streams into a single destination stream to improve backup performance to tape.

13 How a Storage Policy Works - 43 Combining Streams Consolidate source streams to fewer destination streams to more efficiently use media. Data Verification Verify chunk integrity for protected data. Erase Media Mark media to be erased after all jobs on media exceed retention. Erasing media will write a new OML header to media making existing data unrecoverable through the CommVault software. Media Refresh Set parameters for when existing data on storage will be copied to new storage. This can be useful to consolidate jobs across multiple tapes to a new tape or when transitioning from an old tape library to a new one. Specify Source Copy For secondary copies this specifies which storage policy copy will be used as the source. Enable Inline Copy When data is being protected to the primary copy it can simultaneously be copied to a secondary copy. Enable Parallel Copy When auxiliary copy jobs run, two secondary copies can be created simultaneously. Defer Auxiliary Copy Specify number of days before an auxiliary copy will run for the secondary copy. Throttle Network Bandwidth Limit the number of Megabytes that can be moved per hour. Backup Selection This is a mandatory configuration for a Selective Copy and can optionally be configured for a Synchronous Copy. This determines the effective start point where the copy will become active.

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