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Using the Volume Shadow Copy Service

  • Article
  • 01/07/2021

VSS backup and restore operations each use a protocol for the interaction of the systems that use mass storage (writers) and those that back it up (requesters).

Both backup and restore operations are primarily driven by the requester, which controls writer and provider behavior by generating systemwide COM events for the writer to process. Because event-generating methods are asynchronous, writers do have limited control into the requester's state through the asynchronous handlers available to VSS (see IVssAsync).

This interaction requires basic data structures describing files and groups of files (components), as well as a metadata model to allow the storage of backup information and to permit writer/requester communication.

 

 

Additional resources

Documentation

  • Shadow Copy Context Configurations - Win32 apps

    Requesters control a shadow copy's features by setting its context. This context indicates whether the shadow copy will survive the current operation, and the degree of writer/provider coordination.

  • Configuring VSS - Win32 apps

    By using VSS configuration tools&\#8212;including setting the shadow copy context, choosing a restore method, and changing a restore target&\#8212;writers and requesters control how a backup or restore operation takes place:

  • What's New in VSS - Win32 apps

    The following topics describe the changes in each release of the VSS API: