Overview of VSS

VSS (Volume Shadow Copy Service) is a feature of Microsoft Windows Server that coordinates among data servers, backup applications, and storage management software to support the creation and management of consistent backups. These backups are called shadow copies, or Snapshot copies.

VSS coordinates Snapshot copy-based backup and restore and includes these additional components:

VSS requestor
The VSS requestor is a backup application, such as the application or NTBackup. It initiates VSS backup and restore operations. The requestor also specifies Snapshot copy attributes for backups it initiates.
VSS writer
The VSS writer owns and manages the data to be captured in the Snapshot copy is an example of a VSS writer.
VSS provider
The VSS provider is responsible for the creation and management of the Snapshot copy. A provider can be either a hardware provider or a software provider:
- A hardware provider integrates storage array-specific Snapshot copy and cloning functionality into the VSS framework. The Data ONTAP VSS Hardware Provider integrates the SnapDrive service and storage systems running Data ONTAP into the VSS framework.
  Note: The Data ONTAP VSS Hardware Provider is installed automatically as part of the SnapDrive software installation.
- A software provider implements Snapshot copy or cloning functionality in software that is running on the Windows system.
  Note: To ensure the Data ONTAP VSS Hardware Provider works properly, do not use the VSS software provider on Data ONTAP LUNs. If you use the VSS software provider to create Snapshot copies on a Data ONTAP LUN, you will be unable to delete that LUN using the VSS hardware provider.