Hi,
I've recently switched my SQL Server 2008 setup from iSCSI LUNs to VMDKs on NFS shares. I know some people had issues with this setup but it's working great for me.
The SMSQL snapshots are scheduled daily at 6pm and delete any backups older than 7 days. Usually this works fine, but once every few weeks the backup fails and I end up with a flexclone of my volume and an additional datastore mounted to the VM.
I looked into this today and saw that the backup from 08/10/2012 failed to delete a snapshot from over a month ago.
[18:14:13.027] DELETING BACKUP - [#1]
[18:14:13.027] Deleting snapshot copy sqlsnap__svmsql01_07-12-2012_12.00.37 of LUN D
[18:14:22.098] [SnapDrive Error]: Deletion of backup (sqlsnap__svmsql01_07-12-2012_12.00.37) failed. Reason: (The backup sqlsnap__svmsql01_07-12-2012_12.00.37 was not deleted successfully. Reason : The virtual entity ff6da25f-3297-41f5-9d03-dd50918c54b5 is mounted from backup sqlsnap__svmsql01_07-12-2012_12.00.37. Please unmount it and try again. ).
(SnapDrive Error Code: 0xc0041054)
I checked the NetApp, thinking there might be a stale and locked snapshot there, but that snapshot (sqlsnap__svmsql01_07-12-2012_12.00.37) doesn't exist.
FAS2020-1> snap list NFS_SQL01
Volume NFS_SQL01
working...
%/used %/total date name
---------- ---------- ------------ --------
3% ( 3%) 1% ( 1%) Aug 13 22:00 vsp032(0135099854)_rhf_sm_nfs_sql01.23 (snapmirror)
4% ( 1%) 2% ( 1%) Aug 13 18:06 sqlinfo__svmsql01_08-13-2012_18.02.36
4% ( 0%) 2% ( 0%) Aug 13 18:05 sqlsnap__svmsql01_08-13-2012_18.02.36
5% ( 1%) 3% ( 1%) Aug 12 18:03 sqlinfo__svmsql01_08-12-2012_18.01.24
5% ( 0%) 3% ( 0%) Aug 12 18:03 sqlsnap__svmsql01_08-12-2012_18.01.24
7% ( 2%) 3% ( 1%) Aug 11 18:03 sqlinfo__svmsql01_08-11-2012_18.01.30
7% ( 0%) 3% ( 0%) Aug 11 18:03 sqlsnap__svmsql01_08-11-2012_18.01.30
9% ( 2%) 5% ( 1%) Aug 10 18:04 sqlinfo__svmsql01_08-10-2012_18.02.07
9% ( 0%) 5% ( 0%) Aug 10 18:04 sqlsnap__svmsql01_08-10-2012_18.02.07
14% ( 6%) 8% ( 3%) Aug 09 18:04 sqlinfo__svmsql01_08-09-2012_18.01.36
14% ( 0%) 8% ( 0%) Aug 09 18:03 sqlsnap__svmsql01_08-09-2012_18.01.36
16% ( 3%) 9% ( 1%) Aug 08 18:03 sqlinfo__svmsql01_08-08-2012_18.01.27
16% ( 0%) 9% ( 0%) Aug 08 18:03 sqlsnap__svmsql01_08-08-2012_18.01.27
17% ( 2%) 10% ( 1%) Aug 07 18:04 sqlinfo__svmsql01_08-07-2012_18.01.34
17% ( 0%) 10% ( 0%) Aug 07 18:03 sqlsnap__svmsql01_08-07-2012_18.01.34
Next I'm checking SnapDrive on the server and the snapshot shows up there!

Any ideas where that snapshots comes from and how to remove it? I'm thinking that SnapDrive might get it from VSC, but I can't even find a list of snapshots in VSC to check this.