For Windows iDataAgents that
support
it, Microsoft's Volume Shadow Copy Service (VSS) and Shadow Copy enable you to produce uncorrupted
snapshots of volumes. VSS coordinates the copy activities between the snap engines,
the applications, and the hardware. Shadow Copy is a software provider in
the VSS scheme, which means that it creates the snapshot (shadow copy) of the data
that you want to protect. There are also hardware providers for VSS, but not all
agents support hardware providers.
VSS serves multiple purposes:
For the supported Windows File System, Exchange, and SQL Server
iDataAgents, VSS enables you to create
a shadow copy of the volume or database so that your backups can proceed uninterrupted
by I/O and open/locked file conditions. Shadow Copy, the VSS software provider,
is the only supported provider for this functionality.
For the Image Level iDataAgent,
VSS enables you to create a snapshot of a volume to be backed up. Only the software
provider is supported for this functionality.
For the ProxyHost iDataAgent,
VSS enables you to create a snapshot of a volume to be backed up. Only hardware
providers are supported for this functionality.
For the Quick Recovery Agent, QR Volume Creation and hardware snapshots
can be coordinated through VSS. In addition, snapshots can be created, mounted,
and deleted. These snapshots can also be made writable upon import.
For ContinuousDataReplicator, VSS can be used for the creation of source
snapshots and Recovery Points. If the source computer has CDR VSS Provider
installed, then the VSS quiesce method is used to perform quiescing of
Exchange and SQL data. If
CDR VSS Provider is not installed then the legacy quiesce method is used for
creating a Consistent Recovery Point.
For a description of the available providers and environments within the context
of the supported agents, refer to the configuration links below.
VSS configuration differs depending upon the agent with which it is working;
select your Agent from the following list for specific configuration information
and procedures: