Image level backup of VM machine fails with Failed to Snapshot VM (4047636)

Date – 2011-07-15
Affected Product: Netvault Backup Vmware Plugin
OS Version – Any
Plugin version: 2.x +
Application version: N/A
Versions: NV 8.5+

Description:
Image level backup of VM machine fails with ‘Failed to Snapshot VM’


Symptoms:

Backing up a virtual machine with VM plugin 2.1.5 with Vsphere the backup fails with ‘Failed to SnapshotVM’. The job will then either fail if this is the only image being backed up or go onto to Snapshot the next VM image in the selection. This error will be limited to certain VMs and will not occur randomly between VMs . If the snapshot fails for a specific VM it will fail every time an attempt is made to backup this VM.
The following errors are seen in the NV binary log:
Job Message 2011/07/08 23:21:12 38 Data Plugin swdfile01 Proceeding to snapshot the VM

Error 2011/07/08 23:21:28 38 Data Plugin swdfile01 Failed to snapshot VM

VMWVIM 207 0 222128 Task to create VM snapshot failed with reason 'Operation timed out.'

It will be possible to create a snapshot for this image manually outside of Netvault in the Vsphere client. When running the backup within Netvault ‘snapshot operation timed out’ will be seen in the Recent tasks Window in the Vsphere client as an attempt is made to create a snapshot.

There is an inconsistency within vSphere between the Snapshot Manager and the number of Snapshot files in the directory for the VM in question within the datastore.

There is probably some inconsistency on the Vmware side between the Snapshot Manager and the number of Snapshot files in the directory for the VM in question within the datastore.

Go into the Snapshot Manager on the Vsphere client and make a note of Snapshots and dates created for this VM.
Go into the directory for this VM on the datastore and check the number and dates against the vmsn files in this directory.

These are created when a snapshot is created for this VM. They should correspond with the snapshots seen in the Snapshot Manager. If not, this could be the cause of the problem. There could still be vmsn files existing for snapshots which have already been deleted in the Snapshot Manager. Restarting the VM resolved the problem. This is because the link to the old snapshot(s) was broken and the obselete vmsn files removed.

BakBone SFDC Solution Number: 00006347