Why is Microsoft Volume Shadow Copy (VSS) So Important to Backup?

As time progresses, more and more backup applications (including ROBOBAK) are becoming Volume Shadow Copy (VSS) aware. VSS is a technology developed by Microsoft that allows a backup application to safely backup locked and open files. VSS works by creating a snapshot of the entire drive and then provides this information to the backup application so that the application can utilize the snapshot.

Volume Shadow Copy is supported on Windows XP, Windows Vista, Windows Server 2003/2008, Windows 7 and above. Both the backup application and software application must be VSS aware to utilize VSS to backup open and locked files. Legacy applications tend to NOT be VSS aware, forcing users to find other methods to backup those open and locked files. Other options to backup open and locked files include open file drivers and Pre/Post scripts to shut off/start an application before and after backup so that the data’s integrity is guaranteed.

Some VSS Limitations:

– Only supported on Windows XP, Windows Vista, Windows Server 2003, Windows Server 2008, Windows 7 and above.
– Only local disks are supported.
– Windows XP only allows one shadow volume to be created per drive at any one time.
– The software program that created the open or locked files needs to support VSS.
– The Microsoft Volume Shadow Service must be enabled in the O/S.
– The machine must have devices that are enabled and associated with the Volume Shadow Service.
– The system must have an NTFS partition that must exist on an internal drive, with at least 100MB of free space for the shadow copies.
– The drive that contains locked files must have free space available.
– VSS can fail if there is too much disk activity.