Article ID: 951288 - View products that this article applies to.
Consider the following scenario. You install Microsoft SQL Server on a volume. You use a Volume Shadow Copy Service (VSS) application to back up files on the volume. In this scenario, SQL Server records a backup operation in the backupset history table. This problem occurs even if you did not actually back up the database files of SQL Server.
Note The NTBackup.exe utility is a VSS application.
This problem occurs because VSS calls the SQLWriter service or the Microsoft SQL Server Desktop Engine (MSDE) writer.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Description of the MSDE writer and the SQLWriter serviceThe MSDE writer is included in the VSS framework in Windows XP and in Windows Server 2003. VSS uses the MSDE writer to back up SQL Server 2000 databases. The SQLWriter service is installed when you install SQL Server 2005. VSS uses the SQLWriter service to back up both SQL Server 2005 databases and SQL Server 2000 databases.
How VSS performs a backup operationWhen VSS performs a backup operation on a volume, VSS calls all writers that have data on the volume. This makes sure that the backup is valid. When VSS calls the SQLWriter service or the MSDE writer, the SQLWriter service or the MSDE writer inserts a record into the backupset history table. This record shows that a backup operation was performed. However, the SQLWriter service or the MSDE writer cannot determine whether the files that VSS backed up are database files.
Precautions to take if you use the entries in the backupset history table for data recoveryIf you want to use entries in the backupset history table for data recovery, you must verify that the entries represent actual database backup operations.
How to verify that an entry represents an actual database backup operationTo do this, run the following statement:
In the result, notice the database_backup_lsn column and the is_snapshot column. An entry that represents an actual database backup operation has the following characteristics:
Verify that the backup set has no errorsTo do this, run the following statement:
If the this query returns any results, it means that you do not have good database backups after the reported date. We strongly recommend that you
perform a full database backup as soon as possible and verify that the full database backup is clean.
The is_damaged propertyThe backupset table in the msdb database contains a row for each backup set. The is_damaged property in the backupset table indicates whether damage to the database was detected when the backup was created. Therefore, the backup may be damaged and not restorable.
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For more information about the SQL Writer service, visit the following Microsoft Developer Network (MSDN) Web site:
http://msdn2.microsoft.com/en-us/library/ms175536.aspxFor more information about the backupset history table, visit the following MSDN Web site:
Article ID: 951288 - Last Review: March 28, 2013 - Revision: 2.0