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Using NetBackup for SQL Server with Snapshot Client How SQL Server operations use Snapshot Client

Performance considerations

When a physical file is backed up using the Snapshot Client, the backup will consist of the entire extent. This contrasts with stream-based SQL Server backups where only the actual data content of the objects are archived. For this reason, if you intend to use snapshot technology for backing up SQL Server, then it may be advantageous to use the SQL Server dynamic file allocation to reduce the likelihood that any of the component files contain large areas of empty space.

Another consideration for choosing between file- and stream-based backups concerns how SQL Server zeroes the target disk area prior to a stream-based restores. In some cases, this almost equals the total disk-copy time for restore. For Snapshot Client restores, however, disk zeroing is not done so the total recovery time can be substantially less.

For further considerations on SQL Server disk initialization see “Instant data file initialization” on page 48.

Performing SQL Server snapshot backups

There are no special interfacing considerations for performing Snapshot Client backups of SQL Server. A snapshot backup will be performed if the backup object is a database, a filegroup, or a file and a policy is selected which is configured for Snapshot Client. If a differential or transaction log backup is attempted with an Snapshot Client backup, then the operation will use the selected policy, but a standard database backup will be performed using the configured storage unit.

Performing SQL Server snapshot restores

Backup images that were created from snapshots are displayed on equal footing with standard backup images. That is, all backup items—without regard to method—are displayed in a time-sequenced ordering that respects the composition of the database hierarchy. In addition, no weighting is given in determining an optimal recovery based on the backup method. To determine


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