Volume Shadow Copy Service framework

Volume Shadow Copy Service (VSS) provides a common interface model to generate and manage online snapshots of SQL Server data.

The Microsoft VSS service manages and directs three VSS software components that are used during VSS operations: the VSS writer, the VSS Requestor, and the VSS provider. The VSS writer is the application that stores data on the source volumes. The VSS Requestor is the backup software. The VSS provider is the combined hardware and software that generates the snapshot volume.

The VSS system provider creates and maintains snapshots on local shadow volumes and refers to the default VSS provider that is available with Windows Server. If you use the Windows VSS system provider, no configuration is required. However, you can make changes by using the VSSADMIN commands.

With a VSS hardware and software copy provider, you can create shadow copies of running volumes on demand. A hardware provider uses a hardware storage adapter or controller to manage shadow copies at the hardware level. Data Protection for SQL Server software does not control the VSS hardware provider. The VSS hardware provider is controlled by the hardware vendor. Install and configure the VSS hardware and software provider as required.