SnapManager fails to detach the database snapshot, as a part of backup process
Snapmanager Log
===============
[15:30:19.480] Creating Snapshot of Virtual Disk Drive:
[15:30:19.480] Virtual Disk [F:], Virtual Disk [G:], Virtual Disk [E:]
[15:30:19.480] Snapshot name: sqlinfo__venkn__recent
[15:30:25.202] Snapshot SnapInfo drive(s) successfully completed.
[15:30:25.248] *** VERIFY DATABASE AFTER BACKUP
[15:30:25.248] Collecting verification information...
[15:30:25.248] Getting database backup information from SnapInfo file...
[15:30:25.248] Running verification from local server....
[15:30:25.264] Mounting Snapshot [sqlsnap__venkn__recent] for Virtual Disk E of Computer VENKSAMP
[15:30:41.949] This Snapshot is mounted as the drive [Z:].
[15:30:41.949] Mount Snapshot succeeded.
[15:30:41.980] Using existing connection to server [VENKSAMP]...
[15:30:42.027] Attaching database [VAS__Mount]...
[15:30:42.027] CREATE DATABASE [VAS__Mount] ON PRIMARY (NAME = 'VAS_dat', FILENAME = 'X:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\data\VAS.mdf') LOG ON (NAME = 'VAS_log', FILENAME = 'X:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\data\VAS.ldf') FOR ATTACH
[15:30:43.934] Database attached.
[15:30:43.934]
[15:30:43.934] DBCC CHECKDB (N'VAS__Mount') WITH NO_INFOMSGS, PHYSICAL_ONLY
[16:50:14.443]
[16:50:14.443] DBCC CHECKDB completed successfully.
[16:50:14.443] Detaching database [VAS__Mount]...
[16:50:34.487] Failed to detach the database.
[16:50:34.487] Dismounting Virtual Disk Z of SnapShot [sqlsnap__venkn__recent]...
[16:54:38.657] Dismount Snapshot succeeded.
As a part of backup process, Snapmanager software creates a database snapshot. It verifies the consistency of the backup by running CHECKDB. Once the CHECKDB completes successfully, it detaches the database snapshot.
In some cases it was failing to detach. Later with profiler traces we were able to identify that "AUTO SHRINK" was enabled. Apparently a system process started the shirink operation on the database. Disabling the "AUTO SHRINK" property helped resolve this issue.