IVssCreateWriterMetadata::SetRestoreMethod method (vswriter.h)

Article
10/13/2021

The SetRestoreMethod method indicates how the writer's data is to be restored.

Syntax

HRESULT SetRestoreMethod(
  [in] VSS_RESTOREMETHOD_ENUM method,
  [in] LPCWSTR                wszService,
  [in] LPCWSTR                wszUserProcedure,
  [in] VSS_WRITERRESTORE_ENUM writerRestore,
  [in] bool                   bRebootRequired
);

Parameters

[in] method

VSS_RESTOREMETHOD_ENUM value specifying the method that will be used in the restore operation.

[in] wszService

A pointer to a wide character string containing the name of a service that must be stopped prior to a restore operation and then started after the restore operation takes place, if the value of method is VSS_RME_STOP_RESTORE_START or VSS_RME_RESTORE_STOP_START.

If the value of method is not VSS_RME_STOP_RESTORE_START or VSS_RME_RESTORE_STOP_START, this argument is not used and should be set to NULL.

[in] wszUserProcedure

Reserved for future use. The value of this parameter should always be set to NULL.

[in] writerRestore

VSS_WRITERRESTORE_ENUM value specifying whether the writer will be involved in restoring its data.

Express writers must set this parameter to VSS_WRE_NEVER.

[in] bRebootRequired

Boolean indicating whether a reboot will be required after the restore operation is complete.

Return value

The following are the valid return codes for this method.

Value	Meaning
S_OK 0x00000000L	The operation was successful.
E_INVALIDARG 0x80070057L	One of the parameter values is not valid.
E_OUTOFMEMORY 0x8007000EL	The caller is out of memory or other system resources.
VSS_E_INVALID_XML_DOCUMENT 0x80042311L	The XML document is not valid. Check the event log for details. For more information, see Event and Error Handling Under VSS.
VSS_E_NOT_SUPPORTED 0x8004232FL	The caller specified a VSS_WRITERRESTORE_ENUM value that is not supported for express writers.
VSS_E_UNEXPECTED	Unexpected error. The error code is logged in the error log file. For more information, see Event and Error Handling Under VSS. Windows Server 2008, Windows Vista, Windows Server 2003 and Windows XP: This value is not supported until Windows Server 2008 R2 and Windows 7. E_UNEXPECTED is used instead.

Remarks

There is a single restore method defined for a writer. If the restore method is not overridden, all of the writer's components will be restored using the same method.

Writers override the restore method on a component-by-component basis by setting a restore target, typically while handling a PreRestore event (CVssWriter::OnPreRestore).

It is important to note that despite the fact that restore methods are applied writer-wide, methods are implemented on a per-component basis. For example, if the method specified by the method parameter is VSS_RME_RESTORE_IF_CAN_REPLACE, then all of the files in the component are restored to their original location if they can all be replaced without an error occurring. Otherwise, they are restored to their alternate location if one is specified.

A file should always be restored to its alternate location mapping if either of the following is true:

The restore method (set at backup time) is VSS_RME_RESTORE_TO_ALTERNATE_LOCATION.
Its restore target was set (at restore time) to VSS_RT_ALTERNATE.

In either case, if no valid alternate location mapping is defined, this constitutes a writer error.

A file can be restored to an alternate location mapping if either of the following is true:

The restore method is VSS_RME_RESTORE_IF_NOT_THERE and a version of the file is already present on disk.
The restore method is VSS_RME_RESTORE_IF_CAN_REPLACE and a version of the file is present on disk and cannot be replaced.

Again, if no valid alternate location mapping is defined, this constitutes a writer error.

An alternate location mapping is used only during a restore operation and should not be confused with an alternate path, which is used only during a backup operation.

For more information about restore methods, see Setting VSS Restore Methods.

If the restore method is VSS_RME_STOP_RESTORE_START or VSS_RME_RESTORE_STOP_START, then the correct name of the service must be provided as the wszService argument. For information on writer participation in stopping and restarting services during a restore operation, see Stopping Services for Restore by Requesters.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	vswriter.h (include Vss.h, VsWriter.h)
Library	VssApi.lib