Database Snapshots
This topic describes database snapshots, which are new in Microsoft SQL Server 2005. Database snapshots are available only in the Enterprise Edition of Microsoft SQL Server 2005. All recovery models support database snapshots.
A database snapshot is a read-only, static view of a database (the source database). Multiple snapshots can exist on a source database and always reside on the same server instance as the database. Each database snapshot is transactionally consistent with the source database as of the moment of the snapshot's creation. A snapshot persists until it is explicitly dropped by the database owner.
Unlike default behavior for user databases, a database snapshot is created with the ALLOW_SNAPSHOT_ISOLATION database option set ON regardless of the setting of this option on the primary database or the model system database.
Snapshots can be used for reporting purposes. Also, in the event of a user error on a source database, you can revert the source database to the state it was in when the snapshot was created. Data loss is confined to updates to the database since the snapshot's creation.
Important
Reverting does not work on an offline or corrupted database. Therefore, taking regular backups and testing your restore plan are necessary to protect a database.
Database snapshots are unrelated to snapshot backups, snapshot isolation of transactions, or snapshot replication.
In This Section
| Topic | Description |
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Provides a conceptual overview of the technology of database snapshots. |
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Presents a variety of situations in which database snapshots are useful. |
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Discusses the impact of database snapshots on the source database and the system environment, as well as limitations on the snapshots themselves. |
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Considers some best practices for creating database snapshots and provides a link to a description of how to create them. |
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Discusses the sparse files created for database snapshots and how to view their actual and maximum sizes. |
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Discusses how reverting to a snapshot works and the restrictions on revert operations, and provides a link to a description of how to revert. |
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Discusses deleting snapshots and provides a link to a description of how to delete them. |