THIS TOPIC APPLIES TO: SQL Server (starting with 2016)Azure SQL DatabaseAzure SQL Data Warehouse Parallel Data Warehouse
This topic is relevant only for databases under the full recovery model that contain multiple filegroups.
In this example, a database named
adb contains three filegroups. Filegroups
C are read/write, and filegroup
B is read-only. The primary filegroup and filegroup
B are damaged, but filegroups
C are intact. Before the disaster, all the filegroups were online.
The database administrator decides to restore and recover the primary filegroup and filegroup
B. The database is using the full recovery model; therefore, before the restore starts, a tail-log backup must be taken of the database. When the database comes on line, Filegroups
C are automatically brought online.
The offline restore sequence has fewer steps than an online restore of a read-only file. For an example, see Example: Online Restore of a Read-Only File (Full Recovery Model). However, the whole database is offline for the duration of the sequence.
Before restoring the database, the database administrator must back up the tail of the log. Because the database is damaged, creating the tail-log backup requires using the NO_TRUNCATE option:
BACKUP LOG adb TO tailLogBackup WITH NORECOVERY, NO_TRUNCATE
The tail-log backup is the last backup that is applied in the following restore sequences.
To restore the primary filegroup and filegroup
B, the database administrator uses a restore sequence without the PARTIAL option, as follows:
RESTORE DATABASE adb FILEGROUP='Primary' FROM backup1 WITH NORECOVERY RESTORE DATABASE adb FILEGROUP='B' FROM backup2 WITH NORECOVERY RESTORE LOG adb FROM backup3 WITH NORECOVERY RESTORE LOG adb FROM backup4 WITH NORECOVERY RESTORE LOG adb FROM backup5 WITH NORECOVERY RESTORE LOG adb FROM tailLogBackup WITH RECOVERY
The files that are not restored are automatically brought online. All the filegroups are now online.