Slide 1. Slide 2 Housekeeping. Slide 3 Overview or Agenda

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1 Slide 1 SQL Server Maintenance Plans Jerome Espinoza Database Administrator 1 Slide 2 Housekeeping Please turn off cell phones If you must leave the session early, please do so as discreetly as possible Please avoid side conversation during the session Thank you for your cooperation! 2 Slide 3 Overview or Agenda Introduction The purpose of this presentation is to demonstrate how to implement many of the Best Practices for SQL Server maintenance plans. The benefit to doing this is: Managing data and transaction log files Eliminating index fragmentation Ensuring accurate, up-to-date statistics Detecting corrupted database pages Establishing an effective backup strategy 3

2 Slide 4 Overview or Agenda Introduction Unfortunately, the material presented here cannot possibly be presented in great detail because of the time allotted for one session. This material will be presented conceptually with as much detail as time permits. 4 Slide 5 Agenda 5 Slide 6 Create SQL Server Administration Objects There are several custom database objects required by this maintenance plan that need to exist in each database. This section describes how to build those objects. 6

3 Slide 7 1. Create SQL Server Administration Objects A. Set each SQL Server instance to allow both SQL Server and Windows Authentication B. Create the following objects in each SQL Server instance: i. A login with SA privileges (I use the same name and password in each SQL Server instance) ii. A database named DBAdmin owned by the user created in step (i) iii. A stored procedure named spdbfilespace in the DBAdmin database that will update a table with all of the database file sizes iv. A stored procedure named sposdiskspace that will check the free space to be > 10% of total disk space on each disk v. A table named DB_File_Space, located in the DBAdmin database, in which the stored procedure from step (iii) can record database file size data. 7 Slide 8 1.A Database Authentication Open the server properties window and check the Security tab to be sure that both SQL Server and Windows Authentication are enabled for the server. 8 Slide 9 1.B.i Database Login. 9

4 Slide 10 1.B.ii DB Admin Database 10 Slide 11 1.B.iii spdbfile Space Stored Procedure 11 Slide 12 1.B.iv sposdiskspace Stored Procedure 12

5 Slide 13 1.B.v DB_File_Space Table 13 Slide 14 Maintenance Plans The following pages describe how to setup SQL Server maintenance plan jobs using the SQL Server Management Studio. 14 Slide 15 SQL Server Maintenance Plans 15

6 Slide 16 SQL Server Maintenance Plans 16 Slide 17 SQL Server Maintenance Plans The screen shown Above will appear. Drag a task from the toolbox into the MP and configure as shown on the following pages. 17 Slide 18 Database Backups Database backups are the last line of defense against data loss or corruption and in my estimation the single most import duty performed by a DBA. 18

7 Slide Database Backups 19 Slide Database Backups Your organization should decide what is best regarding backup storage. 20 Slide Database Backups Back Up Database Task is used in this maintenance plan Backup frequency depends on the type of recovery model/backup as per the table on the previous page. Backups expire after 14 days System Administrators are notified in case of job failure 21

8 Slide Database Backups 22 Slide Database Backups 23 Slide 24 Update Statistics Perform this function weekly to update query optimization statistics on a table or indexed view. 24

9 Slide Update Statistics Updating statistics ensures that queries compile with up-to-date statistics. However, updating statistics causes queries to recompile when executed. Do not update statistics too frequently because there is a performance tradeoff between improving query plans and the time it takes to recompile queries. You may want to consider updating your statistics weekly. This can be done over the weekend, or the middle of the night, on all user databases. Also, leave the Auto Update Statistics and Auto Create Statistics properties set to true for your database. The auto update will be invoked much less frequently if you manually force an update every weekend. This is a good thing because you don t want queries recompiling at random times throughout the business week if you can help prevent it. 25 Slide Update Statistics Update Statistics Task is used in this maintenance plan Small databases use a full scan Large databases scan a percentage of the entire database This task is performed on all user databases This task is run weekly off-hours System Administrators are notified in case of job failure 26 Slide 27 Verify Integrity Perform this function weekly to check the allocation and structural integrity of user and system tables, and of indexes in the database. 27

10 Slide Verify Integrity Use the Check Database Integrity Task to check the allocation and structural integrity of user and system tables, and indexes in the database This task is run weekly off hours over the weekend This is accomplished by running the DBCC CHECKDB Transact-SQL statement Running DBCC ensures that any integrity problems within the database are reported, thereby allowing them to be addressed later by a system administrator All User Databases can be checked in one maintenance plan System Administrators are notified in case of job failure 28 Slide 29 Maintenance File Cleanup This feature will remove files related to maintenance plans, including database backup files and reports created by maintenance plans. 29 Slide Maintenance File Cleanup Two Maintenance Cleanup Tasks are used in this maintenance plan First task deletes old database backups > two weeks old Second task deletes old transaction log backups > two weeks old This task is run weekly (after the weekly full backup jobs) System Administrators are notified in case of job failure 30

11 Slide 31 Perfmon/SQL Agent Job Log Cleanup This feature will remove log files created by PerfMon and SQL Agent jobs that are not removed by the Maintenance File Cleanup task. 31 Slide PerfMon/SQL Agent Job Log Cleanup This is a custom maintenance plan designed to cleanup old PerfMon files created by the Alert and Notification System* and SQL Agent log files not removed by the Maintenance File Cleanup task. Execute SQL Server Agent Job Tasks are used in this plan This maintenance plan has two subplans Subplan 1: PerfMon log files will be deleted after 14 days Subplan 2: SQL Agent job log files will be deleted after 90 days This maintenance plan is performed weekly DBA is notified in case of job failure 32 Slide PerfMon/SQL Agent Job Log Cleanup 33

12 Slide PerfMon/SQL Agent Job Log Cleanup Create a SQL Agent job named Delete_Old_PerfMon_Logs with the properties set as follows: The Type should be set to Operating System (CmdExec) Be sure to run as AdminProxy. Will require AdminProxy creation. The command should run the batch file created on the previous page. 34 Slide PerfMon/SQL Agent Job Log Cleanup 35 Slide PerfMon/SQL Agent Job Log Cleanup 36

13 Slide PerfMon/SQL Agent Job Log Cleanup Create a SQL Agent job named Delete_Old_SQLAgent_Logs with the properties set as follows: The Type should be set to Operating system (CmdExec) Be sure to run as AdminProxy. The command should run the batch file created on the previous page. 37 Slide PerfMon/SQL Agent Job Log Cleanup 38 Slide 39 Database History Cleanup This task will delete historical data related to backup and restore activities, SQL Server Agent jobs, and database maintenance plans found in system tables. 39

14 Slide Database History Cleanup The History Cleanup task deletes entries in the following history tables in the SQL Server msdb database. backupfile backupfilegroup backupmediafamily backupmediaset backupset restorefile restorefilegroup restorehistory By using the History Cleanup task, a package can delete historical data related to backup and restore activities, SQL Server Agent jobs, and database maintenance plans. 40 Slide Database History Cleanup The History Cleanup Task should be configured as follows: It should be run once a week Delete SQL Agent job history older than 3 months System administrators should be notified in case of job failure 41 Slide 42 Check Disk Free Space This task will run a custom stored procedure to check the free space on system disks. 42

15 Slide Check Disk Free Space This is a custom task in the maintenance plan that will check each operating system disk to be sure it is under 90% full. If that test fails, the Alerts and Notification system will be used to the SysAdmins and alert them that there is less than 10% free space on the disk. One sure way to grind a database server to a halt is to run low on free disk space. If Windows needs to start paging excessively, while at the same time the database is caching table data, bad results can happen. If a disk containing transaction log files becomes 100% full, the database will freeze until it can write the pending log entry to disk. 43 Slide Check Disk Free Space This maintenance plan uses the Execute T-SQL Statement Task It should be run daily after the backup and cleanup jobs complete There will be one subplan for each physical drive on the system to check it s free space Each subplan will call the sposdiskspace stored procedure Each step will send a failed notice if the disk > 90% full System administrators are notified in case of job failure 44 Slide Check Disk Free Space 45

16 Slide Check Disk Free Space 46 Slide 47 Record Database File Space Utilization This task will run a stored procedure to log the space utilization of all database files in a custom table for reporting purposes. 47 Slide Record Database File Space Utilization 48

17 Slide Record Database File Space Utilization This report is an example where a programmer enabled a feature that caused the database to grow. This report helped to determine the problem at a glance. 49 Slide 50 Checking for Index Fragmentation This is done to determine when indexes require reorganizing or rebuilding due to excessive fragmentation. Fragmentation can be costly in SQL Query performance. 50 Slide Checking for Index Fragmentation Checking for Index Fragmentation is not done as part of the maintenance plan. This is done periodically by the DBA manually. Fragmentation between 10% and 30% consider reorganizing an index (not rebuilding it) Fragmentation over 30% is the cutoff for re-indexing. Re-Indexing large tables will cause excessive logging on full recovery model databases. Full recovery model databases should be set to simple or bulk-logged before re-indexing. If log shipping is in place it should be stopped before re-indexing (this of course will require a resynchronization of the databases after re-indexing has completed). 51

18 Slide Checking for Index Fragmentation 52 Slide 53 Shrinking the Database This is a task built into SQL Server that I recommend to never use. 53 Slide Shrinking the Database There are two options for shrinking database files: 1. Shrinking data files under no circumstances do this. This option should never be used as part of routine scheduled maintenance. 2. Shrinking transaction log files from time to time this may be needed. However, if the rest of this maintenance plan is put into action, it should never be necessary. Regular log backups should keep the transaction log file sizes in check. 54

19 Slide 55 Summary There are three important phases in the life of a database: 1. Design 2. Implementation 3. Maintenance The first step is performed by the software vendor. The second step, while critical, is done once and takes the shortest amount of time. The third step goes on ad infinitum. You will spend most of the life of the database maintaining it, keeping it well tuned, and keeping the data secure. 55 Slide 56 Summary 56 Slide 57 Questions Any Questions? Thank You! Jerome Espinoza Database Administrator jespinoz@lccc.wy.edu Phone: