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Database snapshots
Using snapshots in a database environment allows a database administrator to roll back a production database to one of several recovery points during the day. The storage at a secondary site is used for QA and DR, and forms the basis of the nightly tape backup.
The choice of using differential snapshots at the primary site depends on the update and delete rate associated with the database. A high rate of changes and deletes may force the use of full-copy snapshots. As with all applications, the performance impact of using differential snapshots needs to be assessed prior to implementation. If asynchronous updates are going to the secondary site, the updated interval should be coordinated with the differential snapshot schedule at the primary site. This reduces the amount of time the database needs to be in hot backup mode.
Coordinating snapshots to support critical applications that typically span multiple servers, operating systems and storage systems can be daunting. But the big win may be with mid-tier applications, which often require far less analysis to determine the impact of snapshots and may use only tape for recovery.
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