NetVault Plug-in for SQL Server 11.0

Full Database backups only: When requirements guarantee data protection up to the previous day, performing Full Database backups nightly should be sufficient when one or more of the following conditions exist:

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Backup windows are large.

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Databases are small.

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Updates are infrequent across entire database.

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Databases are only for testing or development purposes.

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Entire database is read-only.

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Full Database and Differential Database backups: When requirements guarantee data protection up to the previous day and backups must be completed quickly, Full Database backups coupled with Differential Database backups is a valid strategy. For example, Full Database backups are performed every Sunday night at 11:00 P.M. while Differential Database backups are performed Monday through Saturday at 11:00 P.M. Each Differential Database backup includes all the changes since the last Full Database backup, which is known as the differential base.

No matter when recovery is performed, the same number of restore jobs is required. For example, if recovery is performed on Tuesday, Sunday’s Full Database backup and Monday’s Differential Database must be restored. Whereas, if recovery is performed on Thursday, Sunday’s Full Database backup followed by Wednesday’s Differential Database backup must be restored.

Even though Differential Database backups increase not only in size but in duration, restores are quicker due to the fewer number of restore jobs that must be run.

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Full File and Filegroup backups and Partial Database backups: When a Simple Recovery Model database includes secondary read-only filegroups, a valid strategy includes Partial Database backups for the primary and read/write filegroups and Full File and Filegroup backups for read-only secondary filegroups. This strategy ensures recoverability of the entire database without requiring backup of the read-only filegroups every time the read/write filegroups are backed up.

Secondary read-only filegroups only need to be backed up once after the initial load and after subsequent updates. When requirements guarantee data protection up to the previous day for read/write filegroups, performing nightly Partial Database backups should be sufficient.

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Full File and Filegroup backups and Partial Database and Differential Partial Database backups: When requirements guarantee data protection for read/write data up to the previous day and backups must be completed quickly, Partial Database backups coupled with Differential Database Backups for the read/write data and Full File and Filegroup backup for the secondary read-only filegroups is a valid strategy.

For example, Full File and Filegroup backups are performed for read-only data only after the initial load and subsequent updates. Partial Database backups, which include the primary filegroup and all read/write filegroups, are performed every Sunday night at 11:00 P.M. In addition, Differential Partial Database backups for the same read/write filegroups are performed Monday through Saturday at 11:00 P.M. Each Differential Partial Database backup includes all the changes since the last Partial Database Backup, which is known as the differential base.

No matter when recovery is performed, the same number of restore jobs is required. For example, if recovery is performed on Tuesday, Sunday’s Partial Database backup and Monday’s Differential Partial Database must be restored. Whereas, if recovery is performed on Thursday, Sunday’s Partial Database backup followed by Wednesday’s Differential Partial Database backup must be restored.

Even though Differential Partial Database backups increase not only in size but also in duration, restores are quicker due to the fewer number of restore jobs that must be run.

Full recovery model backup sequences

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Full Database and Incremental Transaction Log backups: When requirements mandate PIT data protection, performing Full Database backup nightly plus Incremental Transaction Log backups every four to eight hours should be sufficient when one or more of the following conditions exist:

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Backup windows are large.

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Databases are small.

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Updates are infrequent across the entire database.

For example, Full Database backups are performed every night while Incremental Transaction Log backups are performed every four to eight hours. Each Incremental Transaction Log backup includes the transaction logs since the last Full Database or Incremental Transaction Log backup.

Restore sequences that use Incremental Transaction Log backups require that every Incremental Transaction Log backup between the last Full Database backup and the point-of-failure is restored in succession. This process can lead to longer restores and increased intervention to initiate multiple restore jobs. To speed up restores, include Differential Database backups, which reduces the number of Incremental Transaction Log backups that must be restored.

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Full Database and Differential Database and Incremental Transaction Log backups: When requirements mandate PIT data protection and restores of the complete database must be completed quickly, Full Database plus Differential Database plus Incremental Transaction Log backups is an ideal strategy.

For example, Full Database backups are performed every Sunday night at 11:00 P.M. Differential Database backups are performed Monday through Saturday at 11:00 P.M. Incremental Transaction Log backups are performed every hour. Each Differential Database backup includes all the changes since the last Full Database backup, and each Incremental Transaction Log backup includes the transaction logs since the last Differential Database backup.

Restore sequences that use Incremental Transaction Log backups require that every Incremental Transaction Log backup between the last Full Database or Differential Database backup and the point-of-failure is restored in succession. This process can lead to longer restores and increased intervention to initiate multiple restore jobs. To speed up restores, increase the frequency of the Differential Database backups to every four to eight hours. This increase reduces the number of Incremental Transaction Log backups that must be restored. This strategy provides complete protection of the entire database with the simplest administration while supporting multiple restore scenarios.

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Full File and Filegroup and Differential File and Filegroup and Incremental Transaction Log backups: When requirements mandate PIT data protection and restores must be completed quickly, Full File and Filegroup plus Differential File and Filegroup plus Incremental Transaction Log backups is an ideal strategy. This strategy lets you restore a complete database or the files or filegroups that are damaged. By being able to restore only what is needed, restores are faster and data loss is minimized.

For example, Full File and Filegroup backups are performed every Sunday night at 11:00 P.M. Differential File and Filegroup backups are performed Monday through Saturday at 11:00 P.M. Incremental Transaction Log backups are performed every hour. Each Differential File and Filegroup backup includes all changes since the last Full File and Filegroup backup, and each Incremental Transaction Log backup includes the transaction logs since the last Differential File and Filegroup backup.

Restore sequences that use Incremental Transaction Log backups require that you restore every Incremental Transaction Log backup between the last Full File and Filegroup or Differential File and Filegroup backup and the point-of-failure in succession. This process can lead to longer restores and increased intervention to initiate multiple restore jobs. To speed up restores, increase the frequency of the Differential File and Filegroup backups to every four to eight hours. This change reduces the number of Incremental Transaction Log backups that must be restored. This strategy provides complete protection of the entire database with the flexibility to restore only the files or filegroups that are damaged while supporting most restore scenarios.

Defining a VSS backup strategy and reviewing types

Plug‑in for SQL Server provides the following types of VSS backups:

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Full Database backup: Full Database backups are supported by:

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SQL Server® versions: 2005 and later

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Recovery models: All

A VSS Full Database backup backs up database data and all the log files necessary to bring the database up to a transactionally consistent state at restore time. Full Database backups consume more space and time per backup and are typically supplemented by differential backups, which are created more frequently. With Full Database backups, you can re-create an entire database in one step by restoring the database.

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Differential Database backup: Differential Database backups are supported by:

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SQL Server® versions: 2005 and later

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Recovery model: All

A VSS Differential Database backup backs up only the data that has changed since the most recent base Full Database backup. A Differential Database backup contains only those parts of the database files that have changed. Differential Database backups are smaller and faster to create than the Full Database backups. A Differential Database backup is useful if some of the database’s tables are modified more frequently than others. In this case, Differential Database backups allow you to back up frequently without the overhead of Full Database backups.


	IMPORTANT: If a failover occurs in an Active/Passive Failover Cluster and your VSS-based backup strategy includes Differential Database backups, perform a Full Database backup of the modified configuration as soon as possible. When the plug-in detects that a failover occurred and a different node holds the active role, the plug-in automatically runs a full backup for the next scheduled backup. However, if you must perform a restore to the new active node before a new full backup is run, database changes that occurred between the last full backup and the new full backup might be lost.