Using snapshot technology with the SQL Agent

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Backup Exec uses snapshot technology by default for SQL Server backups. The SQL Agent supports full snapshot backups using Microsoft's Volume Shadow Copy Service (VSS), a snapshot provider service only available on Windows 2003 or later. The use of snapshot technology can reduce both restore time and backup performance on the server.

When you submit a backup job that uses snapshot technology, a snapshot of each volume is created, providing a point-in-time record of the data. Backup Exec uses snapshot technology to momentarily suspend write activity to a volume so that a snapshot of the volume can be created. The data is then backed up from the snapshots, and then the snapshots are deleted.


Use snapshot technology with jobs that use deduplication devices.

Before you use snapshot technology with the SQL Agent, review the following information:

  • With snapshot technology, a point-in-time view of the SQL database is "snapped" and then backed up, leaving the actual SQL database open and available for users.

  • SQL backups that use snapshot technology are considerably larger than regular SQL backups (also known as streaming backups).

  • Performing consistency checks before backup is strongly recommended.

    See Configuring Backup Exec to run a consistency check before every SQL backup

  • The SQL Agent supports only full snapshot backups; transaction log snapshots and differential snapshots are not supported.

  • With the SQL Agent, snapshot and streaming backups are interoperable when you restore SQL data.

  • Performing database consistency checks both before and after backups affects the time required for the backup jobs.

The following SQL backup options are not supported with snapshot backups:

  • Use checksums on backup (SQL 2005 or later)

    This option is used as a redundancy check, and works with the Run verify only and do not restore data restore option.

  • SQL Server 2008 Enterprise Edition software compression

  • Create on-disk copies of SQL backups to be placed on the SQL Server where the database is located


Microsoft Virtual Shadow Copy Service (VSS) snapshots are not the same as SQL database snapshots. VSS snapshots enable you to create point-in-time snapshots of disk volumes and shares; database snapshots enable you to create point-in-time copies of SQL databases.


See Using database snapshots for SQL Server.

Terms of use for this information are found in Legal Notices.



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