This post look at a new class of VSS writers enabled in Windows 7 (download) and Windows Server 2008 R2 (download) that lower the cost for applications to participate in backups. The Volume Shadow Copy Service or VSS as its better known is the backup infrastructure in Windows. Data protection applications (requesters) use VSS to create snapshots of volumes for various purposes including data mining and backups. Backup agents rely on VSS writers to ensure that application data is in a consistent state on disk before creating a snapshot or point-in-time image of one or more volumes. The snapshot itself may be used as the backup or the data may be copied from it to tape.
More Info: Storage Team