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Services Utility: Volume Shadow Copy Service

Display Name (?): Volume Shadow Copy
Short Name (?): VSS
Executable (?): vssvc.exe
Library (?): None.
Depends On (?): Remote Procedure Call (RPC)
Supports (?): None.
Description (?): Manages and implements Volume Shadow Copies used for backup and other purposes. If this service is stopped, shadow copies will be unavailable for backup and the backup may fail. If this service is disabled, any services that explicitly depend on it will fail to start.
OS (?): NT4 Server, 2000 Server, Server 2003, Vista Server
Startup (?):

Explanation (?):

The Volume Shadow Copy service provides the ability for a server to take delta snapshots of stored data. This service works in conjunction with the MS Software Shadow Copy Provider service to provide native streamlined backup abilities. When this feature is enabled, meaning it is turned on and there is a server infrastructure in place to take advantage of it, a user can recover deleted files and revert to previous versions of a file. This feature is very handy and could provide a server administrator a great deal of hassle as he wouldn't have to go through tape backups in order to find a less recent version of a file. This service provides the actual mechanism for backing up and restoring files, whereas the provider service just organizes the backups.

Previous versions of Windows had no native method for performing a complete backup of files on a server. Nor was there the ability to revert files stored on a server to previous revisions. However, with Windows XP and Windows Server 2003 you can take advantage of the Volume Shadow Copy service. This component of Windows is able to take a complete backup of a server's data at boot, and then is able to modify the backup with changes (deltas) as time goes on. Although it should be noted that file changes are calculated on schedules. This means that it is possible for you to retrieve files that you have deleted, and it is possible to return to a previous version of a file, such as a document, if you were to make mistakes you did not like. From the server side the backups take up less space than expected because the original file is saved, along with the changes, instead of several copies of the same file.

This component of Windows also provides the ability for the server to backup files that are locked. This means that if you have a file open that the Windows server can, in the background, remove the file handle, backup the file, and then return the file handle to your workstation without you ever being the wiser. This means that there are no files skipped during the backup process. This means that administrators do not need to have formal backup times, as the backup could be performed at any time of day. However, this means that a replica of the file must be produced at the time of unlocking it, so the space to duplicate the file must be available on the server.

If you did not understand the above then you most likely do not need to worry about it. This service is only needed in a corporate environment where there are workstations and servers that need centralized backup. Normally this service would be used for fairly large infrastructures on a domain, but it could also be used for a small business. If you are using this service then you may want to set it to automatic. If you do not use this, like most people, then you should leave it set to manual as it is only started when needed.

Please visit /tools/services/ for the complete Services utility.