Troubleshooting VSS issues for StorageCraft ShadowProtect
External applications like StorageCraft shadow protect, uses the correct API calls to VSS (these calls are referred to as VSS Writers) to freeze relevant application. During the process of creating the backup, VSS tells the application to commit all transactions to disk and then freezes the database, to create the backup. This freezing process allows the data to read from the frozen sectors and blocks writing to these same sectors.
Whenever backup failure alert comes, check the SPX application, and it will show that the incremental backup has failed due to “unable to take a snapshot of the volume”
Check the VSS writer status using the below command:
vssadmin list writers
As per the above screenshot, most of the VSS Writers are in the failed state.
Restart the Volume Shadow Copy service, and it will restart the dependent service too (StorageCraft Shadow Copy Provider), and again check the VSS Writer status, if it is showing as “No error” and stable state, then the issue is fixed, and the backups will be OK.
After the volume shadow copy service restart, if the VSS Writers are still in failed state, then open the Event Viewer and look for any VSS related errors, and you can see something like below screenshot
The Application event IDs 12293, 12298, 6 are for VSS operation and 12291, 8193 are for COM+ Event system. In summary, the VSS service failed during, to commit the snapshot due to Semaphore timeout.
Run the below command to list the VSS providers:
vssadmin list providers
As per the above screenshot, the failure occurred while calling the StorageCraft Volume Snapshot Software Provider to commit the snapshot and the Semaphore timeout.
In order to test, whether the StorageCraft Volume Snapshot Software Provider is successfully taking snapshots, run the following command,
vssadmin create shadow /for=c:
If it is successfully creating snapshots as below screenshot, the backups will be OK now. Try re-running the incremental backup using SPX and it will be successful using VSS service.
Written by Logendra