VSS is a Microsoft Windows technology that is used to take backup copies on specific data volumes. The main purpose of VSS is to:
- Create consistent snapshots where data integrity is ensured
- Workaround any file-locking issues on the volume by creating a read-only copy first
VSS is used in conjunction with VMware ESXi/ESX to create quiesced backups of Windows 2003 or later guest operating systems and with VMware Converter.
To troubleshoot issues with VSS, VMware recommends that you collect:
VMware Tools logs
To collect VMware Tools logs:
- Enable debug logging for VMware Tools. For more information, see Enabling debug logging for VMware Tools within a guest operating system (1007873).
- Download, extract, and run DebugView on the Windows machine. Check these options:
- Capture > Capture Win32
- Capture > Capture Global Win32
- Capture > Capture Kernel
- Capture > Passthrough
- Capture > Capture Events
- Options > Clock Time
- Options > Show Milliseconds
Note: On systems that have UAC (Windows Vista and later), run DebugView as administrator by right-clicking on the icon and choosing Run as administrator.
- Start the capture and replicate the VSS error. DebugView begins recording all VSS actions.
- Save the contents to a file.
VSS trace logs
To capture VSS trace logs:
vsstrace.exe is available in the Microsoft Windows Software Development Kit (SDK). You can download Microsoft Windows SDK from the
Microsoft Download Center.
Run this command, then reproduce the issue to gather vsstrace logging:
vsstrace.exe -l 140 +f 0xffff > vss.trace.log
Note: For more information on this command, see the Microsoft article
Using Tracing Tools with VSS.
vssadmin
vssadmin is a tool provided with Windows 2003 or later operating systems to list VSS information and modify settings.
To display a list of all VSS providers installed on a system, run the command:
vssadmin list providers
The output appears similar to:
Provider name: 'Microsoft Software Shadow Copy provider 1.0'
Provider type: System
Provider Id: {b5946137-7b9f-4925-af80-51abd60b20d5}
Version: 1.0.0.7
Check for any non-vmware and non-Microsoft providers that may be listed
To display a list of all VSS writers, run the command:
vssadmin list writers
Immediately after a VSS failure, run this command to see the component that failed.