Introduction to NetBackup for SQL Server Technical overview
select an object for backup, the GUI creates a batch file that contains a script. The SQL Server database agent interprets this script. You can either execute the script immediately or save it to run later. You can run a script later by including it in the backup selections list of a backup policy.
When a backup script is executed, NetBackup for SQL Server does the following: generates an SQL backup statement, logs into SQL Server, and delivers the SQL statement to SQL Server through ODBC. Next, the database agent connects to SQL Server through one or more VDI objects. One virtual device is created per backup stripe. In addition, a VxBSA session is initiated for each stripe. These separate sessions allow NetBackup to start a backup job for each stream that is generated from SQL Server.
When the backup completes, the database agent obtains detailed properties of the object that was backed up, including its relationships to other objects. The agent writes this information to the NetBackup catalog and associates it with the backup image. If there are multiple stripes, then the metadata is associated with the first backup image. The adjunct stripes are associated with one another based upon a common naming convention.
How does NetBackup for SQL Server recover a database?
The NetBackup MS SQL client displays backup images in a logical hierarchy that mirrors the composition of the database. If you select a transaction log or differential image, then NetBackup examines the metadata that is stored with the images for the selected database. It then determines the most efficient recovery set. Then the agent generates a batch file that includes a sequence of scripted restores. When the scripts are executed, the database is recovered.
The individual restore operations work in a similar manner to backups. An SQL restore statement is generated and provided to SQL Server by ODBC. A VDI connection is made. Then a VxBSA session is initiated in order to start the data flow between the media manager and SQL Server. NetBackup determines the number of streams (and the corresponding virtual devices and VxBSA sessions) by the number of stripes that were generated during backup.
After all of the recovery operations have completed, the NetBackup agent takes the final step that sets the database into the recovered state. The database goes back online and becomes available for use.
What factors impact the data transfer rate during a SQL Server backup or restore operation?
To optimize your system for SQL Server backups the first step is to tune your environment for standard backup operations. Details are provided in the NetBackup Backup Planning and Performance Tuning Guide. With this