Volume Shadow Copy Service Support with Distributed Transactions
Applies To: Windows Server 2008
The Volume Shadow Copy Service (VSS) provides backup and restore functionality for disaster recovery. VSS was first provided in Windows XP and Windows Server 2003. In Windows Vista and Windows Server 2008, the Distributed Transaction Coordinator service (MSDTC) now provides some support for VSS where the following Windows backup and restore applications are used:
In Windows Vista, System Restore and Windows Complete PC Backup, respectively, provide backup and restore of system-only files or complete backup and restore of all files on the computer.
In Windows Server 2008, Windows Server Backup provides backup and restore for server data.
When you use either of these utilities to perform backup and restore operations in the specified versions of Windows, you can simply schedule the backups or perform restore operations. There is no need for additional action to ensure transactional consistency when the limitations that are described in the following section are not applicable.
Limitations of VSS support for distributed transactions
VSS operations are limited to the local computer. Where Microsoft Distributed Transaction Coordinator (MS DTC) support for VSS is available, it is limited to local deployment and transaction coordination scenarios. The following configurations are not supported:
Any cluster topology
Any remote proxy topology where the MSDTC service from a remote computer is used to coordinate transactional activity locally
Any application topologies that involve distributed transactions
Also, starting with Windows Server 2008, in Windows Server Backup you have the option to restore only a single directory or file. Restoring the folder where the MS DTC log file is located may result in transaction loss. Therefore, data corruption can occur if Windows Server Backup is used to restore the MS DTC log file or the folder where the log file is located. For more information about Windows Server Backup, search for "backup and recovery overview" in Windows Server 2008 Help.