I’m currently working on a project and have come across issues with VSS writers affecting netbackup and causing backups to fail.

The Environment:
2 x Windows 2008 Enterprise x64 Servers
Hardware: Blades
Memory: 16GB
Disk Space: C: 40Gb, D: 100GB
Services: DFSR, Citrix XenApp 5.0, Netbackup, Terminal Server.

VSS: We are snapshotting the volumes every 6 hours.
DFSR: We have been replicating user profiles and data from Server A to Server B.

The issue: We detected the problem when the backups of Shadow Copy Components started failling. After close investigation on Server A we found none of the VSS writers were listing. The VSS writers are used by Netbackup as API to backup replicated folders and the system state.

Application Logs Events:

Log Name:      Application
Source:           VSS
Date:              04/01/2010 01:51:17
Event ID:         12291
Task Category: None
Level:             Error
Keywords:      Classic
User:              N/A
Computer:      ServerA
Description:
Volume Shadow Copy Service error: Error on creating/using the COM+ Writers publisher interface: BackupShutdown [0x8000ffff].

Log Name:      Application
Source:           VSS
Date:              04/01/2010 01:51:18
Event ID:         12301
Task Category: None
Level:              Error
Keywords:      Classic
User:          N/A
Computer:      ServerA
Description:
Volume Shadow Copy Service error: Writer ASR Writer did not respond to a GatherWriterStatus call.

Operation:
Gather writers’ status
Executing Asynchronous Operation
Context:
Current State: GatherWriterStatus

Log Name:      Application
Source:           VSS
Date:              04/01/2010 01:51:18
Event ID:         12347
Task Category: None
Level:             Error
Keywords:      Classic
User:              N/A
Computer:      ServerA
Description:
Volume Shadow Copy Service error: An internal inconsistency was detected in trying to contact shadow copy service writers.  The Registry Writer failed to respond to a query  from VSS. Please check to see that the Event Service and Volume Shadow Copy Service  are operating properly, and please check the Application event log for any other events.

Operation:
Gather writers’ status
Executing Asynchronous Operation
Context:
Current State: GatherWriterStatus

Resolution: In the system registry check that “eventcls.dll” has the path of %SystemDrive%\system32\evencls.dll. You may need to register the dll in the system if you are unable to find any listed. The path in this example was:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\EventSystem\{26c409cc-ae86-11d1-b616-00805fc79216}\EventClasses\{FAF53CC4D73-4E36-83F1-2B23F46E513…

If the path is found to be incorrect and has since been corrected you may need to restart the following services:

  1. COM+ Event Syste,
  2. Volume Shawdow Copy

These events plus EventID: 32 normally indicate that something is wrong in the system registry with the VSS DLL depenances.

For more information please look at the following technet article http://social.technet.microsoft.com/Forums/en/winservergen/thread/5ce377db-3c2e-454f-a003-ec51e80232ce

Please also read my blog on VSS Writer: Shadow Copy Optimization Writer disappearing.