Using VSP with Databases

There are special considerations regarding using VSP (Volume Snapshot Provider) to back up and restore databases.

Many popular database vendors provide a formal application program interface (API) specifically designed for use with backup products. VERITAS works closely with many database vendors to ensure these interfaces are stable, efficient, and reliable when used in conjunction with NetBackup and the various NetBackup database extension features. Many of these APIs were jointly developed to ensure that data is protected and can be restored when needed. Oracle, Microsoft (SQL Server, Exchange), IBM (Lotus Notes, DB2), NCR (Teradata), Sybase and Informix are examples of database vendors that provide an API for use with backup products. VERITAS strongly recommends that the NetBackup database extension features be used when a backup API is available and when backing up a database in a hot mode is required.

This property appears for Windows clients only.

Databases with an API

Hot backups are done on active databases and only by using these formal APIs will the confidence of a backup and the ability to perform a successful restore be achieved. VERITAS does not recommend that VSP be used for hot backups of these databases.

Cold or inactive backups of these databases may be possible with VSP, but success varies with each database vendor. Customers should contact the specific database vendor to identify the recommended method for database backup where data reliability is ensured as database programs recover from a point-in-time restore differently. If the data being backed up and restored does not conform to the specification designed into the database product being used, the integrity of the database can be in question.

Databases without an API

When using VSP to back up databases that do not have a backup and restore API, the safest method is to back up the databases when the database is inactive (cold). For databases where there is no VERITAS database extension product, shut down the database and perform a file system level or cold backup.

If the databases cannot be backed up cold and the only option is a hot backup, set Busy File Wait to 5 seconds. If the file system does not achieve a quiescent or inactive state, NetBackup will not perform the VSP snapshot. NetBackup does not fail the backup when a quiescent state is not achieved. Instead, NetBackup continues the backup as if VSP was not being used. The result is that NetBackup skips open, active, or locked files. The backup job ends with an exit status code 1, indicating that the backup job completed but not all files were successfully backed up.

If VSP is used to back up database environments, VERITAS strongly recommends first backing up the data and validating that the backup exited with a Status 0. Then, restore the database and confirm the integrity of the data and the functionality of the database.

Using VSP to back up active databases without using a formal API presents risk. Customers should contact the database supplier to ensure support of database backups using point-in-time technology. Also, significant back up and restore testing should be performed to assure database availability and reliability.