Windows Server 2008 R2 File System Technologies - Volume Shadow Copy Service (VSS)

Windows Server 2003 introduced a file system service called the Volume Shadow Copy
Service (VSS). The VSS enables administrators and third-party independent software vendors to take snapshots of the file system to allow for faster backups and, in some cases, point-in-time recovery without the need to access backup media. VSS copies of a volume can also be mounted and accessed just like another Windows volume if that should become necessary.


Shadow Copies of Shared Folders
Volume shadow copies of shared folders can be enabled on Windows volumes to allow administrators and end users to recover data deleted from a network share without having to restore from backup. The shadow copy runs on a scheduled basis and takes a snapshot copy of the data currently stored in the volume. In previous versions of Windows prior to Windows Server 2003, if a user mistakenly deleted data in a network shared folder, it was immediately deleted from the server and the data had to be restored from backup. A Windows Server 2003, Windows Server 2008, or Windows Server 2008 R2 NTFS volume that has shadow copies enabled allows a user with the correct permissions to restore deleted or overwritten data from a previously stored shadow copy backup. It is important to note that shadow copies are stored on local volumes and if the volume hosting the shadow copy becomes inaccessible or corrupted, so does the shadow copy. Shadow copies are not a replacement for backups and should not be considered a disaster recovery tool.


Volume Shadow Copy Service Backup
The Volume Shadow Copy Service in Windows Server 2008 R2 also provides the ability for Windows Backup and third-party software vendors to utilize this technology to improve backup performance and integrity. A VSS-compatible backup program can call on the Volume Shadow Copy Service to create a shadow copy of a particular volume or database, and then the backup can be created using that shadow copy. A benefit of utilizing VSSaware backups is that the reliability and performance of the backup is increased as the backup window will be shorter and the load on the system disk will be reduced during the backup.

Source of Information : Sams - Windows Server 2008 R2 Unleashed