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The Volume Snapshot Service (VSS), also known as Volume Shadow Copy Service, is a technology included in Microsoft Windows that allows taking manual or automatic backup copies or snapshots of computer files or volumes, even when they are in use.
The Accredo VSS Writer is backup software that plugs into Windows VSS. It makes use of Windows VSS, so that VSS clients such as ShadowProtect can take consistent snapshots of Accredo while it is in use.
The Accredo VSS Writer can be asked to briefly "freeze", which will prevent writes while the Snapshot is taken, and then "thaw", which will allow writes. Taking a Snapshot on a server usually takes less than a minute (typically around 15 seconds) with time taken influenced mostly by writes which are currently in progress that must be completed before the Snapshot can be taken.
Use with The Accredo VSS Backup utility or a third-party backup solutions that supports volume snapshots, as this will allow backups to be seamlessly made while Accredo is in use.
Installing the Accredo VSS Writer
The SetupAccredoVSS.exe file is the installer. Install this on the Server where Accredo is installed.
The AccredoVSSWriter.ini file sets the configuration for the VSS service. In the ini file, the System path must point to the Accredo System it is managing. The ini file needs to be in the same directory as the installed exe file.
The correct version of the service must be installed to match the operating system, either 64 bit or 32 bit. The installer should detect and install the correct version automatically.
Running the Accredo VSS Writer
Start the VSS either from the Windows Services Manager or from the command line.
VSS Options:
The service links to the VSS structure that the backup clients will be talking to.
VSS Ini File
Output for the VSS Writer defaults to the .exe directory, with a file name of AccredoVSSWriter.Log, unless an output default file is specified in the .ini file.
A sample .ini file is:
[Config]
SystemPath = c:\Saturn400
// StopEventLogOutput controls whether messages get output to the Windows event log
StopEventLogOutput = FALSE
// Also write output messages to the OutputLog file
OutputLog = c:\data\VSSWriter.Log
// 0 = Critical only
// 1 = Important + Critical
// 2 = Information + Important + Critical
Verbosity = 2
// the maximum amount of time (milliseconds) to spend acquiring a Freeze/Thaw
FreezeAcquireTimeout = 60000
// If the VSS crashes, IncludeMiniDump will create a *.dmp file and add a stacktrace to the output log
IncludeMiniDump = TRUE
VSS Admin
Note that some VSS Admin tools do not involve writers when creating snapshots. This can be checked by running the VSS Admin lists shadows and checking that writers display in the attributes.