Note The NTBackup.exe utility is a VSS application.
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:
SELECT server_name, database_name, backup_start_date, is_snapshot, database_backup_lsn
- The value of the database_backup_lsn column is not 0.
- The value of the is_snapshot column is 0.
Verify that the backup set has no errorsTo do this, run the following statement:
WITH backupInfo AS( SELECT database_name AS [DatabaseName],
name AS [BackupName], is_damaged AS [BackupStatus],
backup_start_date AS [backupDate],
ROW_NUMBER() OVER(PARTITION BY database_name
ORDER BY backup_start_date DESC) AS BackupIDForDB
FROM msdb..backupset) SELECT DatabaseName
FROM backupinfo WHERE BackupIDForDB = 1 and BackupStatus=1
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.
|Rule software||Rule title||Rule description||Product versions against which the rule is evaluated|
|System Center Advisor||SQL Server Database Backupset is marked as Damaged||In this SQL Server instance advisor detected the presence of one or more backupset marked as "damaged" in MSDB database. This means that the Backup file is damaged and essentially the database is exposed and the backup potentially non-restorable. Review the Information Collected section and ensure that a subsequent good backup is available for the database in question. Refer to the KB article for more details.||SQL Server 2008 |
SQL Server 2008 R2
SQL Server 2012
Номер статьи: 951288 — последний просмотр: 28 марта 2013 г. — редакция: 1