Customizing VSS Snapshots

Problem: You want to change how your A3 takes VSS snapshots on your Windows machine

Solution: Customize the snap.ps1 PowerShell script in c:\program files\QSBAgent\bin

VSS, or Volume Shadow Service, is the Microsoft mechanism to snapshot your Windows volumes. Starting in A3 7.5, when protecting a Windows machine via the Agent method, Alike will invoke the snap.ps1 PowerShell script in your installation directory in order to conduct a VSS snapshot. 

Windows Servers use the diskshadow tool to create snapshots, and is straightforward to customize in the snap.ps1 file in your agent installation’s bin directory (usually c:\program files\QSBAgent\bin). Look for the lines:

# Diskshadow configuration header

# See 

# https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/diskshadow

$shadowconf = @"

set context persistent nowriters

# set context persistent

set metadata qsmeta.cab

begin backup

create

end backup

"@

To enable all VSS writers, simply comment out "set context persistent nowriters” line and un-comment "# set context persistent"

A specific problem writers can be excluded with the line

writer exclude writername

More information on the command and its features is available from Microsoft documentation.