Identification and resolution of Volume Shadow Copy Service errors
Identification and resolution of Volume Shadow Copy Service errors
Identify the problem writers using vssadmin
vssadmin syntax:
vssadmin list {shadows [/set= [shadow copy set GUID]] | writers | providers}
vssadmin delete shadows /for=<ForVolumeSpec> [/oldest | /all | /shadow=<ShadowID>] [/quiet]`</pre>
Let’s start off by checking the state of the VSS Writers
C:\vssadmin list writers
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool (C) Copyright 2001 Microsoft Corp.
Writer name: 'System Writer'
Writer Id: {e8132975-6f93-4464-a53e-1050253ae220}
Writer Instance Id: {449e12cf-6b8f-4d75-a821-bc869d6612c4}
State: [1] Failed
Last error: No error
Writer name: 'SqlServerWriter'
Writer Id: {a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}
Writer Instance Id: {de3b2861-77f6-43f8-8619-64dc9ea2fbcf}
State: [1] Stable
Last error: No error
Writer name: 'MSDEWriter'
Writer Id: {f8544ac1-0611-4fa5-b04b-f7ee00b03277}
Writer Instance Id: {9036fdfa-05ef-4f7d-9c2f-84fa2f06560a}
State: [1] Stable
Last error: No error
Writer name: 'WMI Writer'
Writer Id: {a6ad56c2-b509-4e6c-bb19-49d8f43532f0}
Writer Instance Id: {f9f92826-a3d4-486c-ade3-a4201deb8ad2}
State: [7] Failed
Last error: No error
The output above is showing the System and WMI writers in a Failed state.
Most issues with VSS can be resolved by a server reboot. Rebooting the server is not often a viable option in a production environment where uptime is an issue. Let’s take a look at some of our other options.
Identify the services associated with the failed writers. Search the registry for the Writer Id and/or Google it.
I have identified the failed writers as: System Writer is the Cryptographic service. WMI Writer is the Windows Management Instrumentation service.
Restart both services and recheck the output of vssadmin list writers
C:\vssadmin list writers
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool (C) Copyright 2001 Microsoft Corp.
Writer name: 'System Writer'
Writer Id: {e8132975-6f93-4464-a53e-1050253ae220}
Writer Instance Id: {449e12cf-6b8f-4d75-a821-bc869d6612c4}
State: [1] Stable
Last error: No error
Writer name: 'SqlServerWriter'
Writer Id: {a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}
Writer Instance Id: {de3b2861-77f6-43f8-8619-64dc9ea2fbcf}
State: [1] Stable
Last error: No error
Writer name: 'MSDEWriter'
Writer Id: {f8544ac1-0611-4fa5-b04b-f7ee00b03277}
Writer Instance Id: {9036fdfa-05ef-4f7d-9c2f-84fa2f06560a}
State: [1] Stable
Last error: No error
Writer name: 'WMI Writer'
Writer Id: {a6ad56c2-b509-4e6c-bb19-49d8f43532f0}
Writer Instance Id: {f9f92826-a3d4-486c-ade3-a4201deb8ad2}
State: [7] Stable
Last error: No error
As you can see above the VSS issues have been resolved by restarting the associated services.
Other VSS errors might not be as straight forward. Let’s looks at some additional options:
Clean up any dead VSS snapshots. Some defect systems accumulate hundreds of VSS snapshots that persist in the system and cause Windows to become unresponsive.
vssadmin delete shadows /all
Restart the services: COM+ System Application Service, Distributed Transaction Coordinator Service, and Volume Shadow Copy Service
Rerun vssadmin list writers and check the output.
Additionally recommended by Microsoft: create a batch file to start/stop the VSS services and reregister the DLLs.
32bit
cd /d %windir%\system32
net stop vss
net stop swprv
regsvr32 ole32.dll
regsvr32 vss_ps.dll
Vssvc /Register
regsvr32 /i swprv.dll
regsvr32 /i eventcls.dll
regsvr32 es.dll
regsvr32 stdprov.dll
regsvr32 vssui.dll
regsvr32 msxml.dll
regsvr32 msxml3.dll
regsvr32 msxml4.dll
regsvr32 Vssapi.dll
regsvr32 Vssui.dll
net start vss
net start swprv
64bit
net stop vss
net stop swprv
regsvr32.exe /i %windir%\system32\eventcls.dll
regsvr32.exe /i %windir%\system32\swprv.dll
regsvr32.exe %windir%\system32\vssui.dll
regsvr32.exe %windir%\SysWOW64\vss_ps.dll
regsvr32.exe %windir%\SysWOW64\msxml.dll
regsvr32.exe %windir%\SysWOW64\msxml2.dll
regsvr32.exe %windir%\SysWOW64\msxml3.dll
regsvr32.exe %windir%\SysWOW64\msxml4.dll
regsvr32.exe %windir%\SysWOW64\ole32.dll
regsvr32.exe %windir%\SysWOW64\oleaut32.dll
regsvr32.exe %windir%\SysWOW64\es.dll
regsvr32.exe %windir%\SysWOW64\comsvcs.dll
vssvc /register
net start swprv
net start vss