IVssProviderCreateSnapshotSet::CommitSnapshots method (vsprov.h)

The CommitSnapshots method quickly commits all LUNs in this provider.

Syntax

HRESULT CommitSnapshots(
  [in] VSS_ID SnapshotSetId
);

Parameters

[in] SnapshotSetId

The VSS_ID that identifies the shadow copy set.

Return value

If any other value is returned, VSS will write an event to the event log and convert the error to VSS_E_UNEXPECTED_PROVIDER_ERROR.

Remarks

This method is called at the defined time at which the shadow copies should be taken. For each prepared LUN in this shadow copy set, the provider will perform the work required to persist the point-in-time LUN contents. While this method is executing, both applications and the I/O subsystem are largely quiescent. The provider must minimize the amount of time spent in this method. As a general rule, this method should take less than one second to complete. This method is called during the Flush and Hold window, and VSS Kernel Support will cancel the Flush and Hold if the release is not received within 10 seconds, which would cause VSS to fail the shadow copy creation process. If each provider takes more than a second or two to complete this call, there is a high probability that the entire shadow copy creation will fail.

Because the I/O system is quiescent, the provider must take care to not initiate any I/O as it could deadlock the system - for example debug or tracing I/O by this method or any calls made from this method. Memory mapped files and paging I/O will not be frozen at this time.

Note that the I/O system is quiescent only while this method is executing. Immediately after the last provider's CommitSnapshots method returns, the VSS service releases all pending writes on the source LUNs. If the provider performs any synchronization of the source and shadow copy LUNs, this synchronization must be completed before the provider's CommitSnapshots method returns; it cannot be performed asynchronously.

Requirements

See also

IVssProviderCreateSnapshotSet