Windows Vista and Windows Server 2008 introduced a set of in-box VSS writers that are responsible for various Windows features.
Note The MSDE in-box writer is not available in Windows Vista, Windows Server 2008, and later. Instead, the SQL Writer should be used to back up SQL Server databases. Only SQL Server 2005 SP2 and later are supported on Windows Vista, Windows Server 2008, and later.
IIS Metabase Writer
In Windows Vista with Service Pack 1 (SP1) and Windows Server 2008, the Internet Information Server (IIS) metabase writer is responsible for enumerating the IIS metabase file. On versions of Windows prior to Windows Vista with SP1, requesters were required to back up the IIS metabase file.
The writer ID for the IIS metabase writer is 59B1f0CF-90EF-465F-9609-6CA8B2938366.
IIS Configuration Writer
In Windows Vista with SP1 and Windows Server 2008, the IIS configuration writer is responsible for enumerating the IIS configuration files. On versions of Windows prior to Windows Vista with SP1, requesters were required to back up the IIS configuration files.
This writer does not back up the .NET FX machine.config file or the ASP.NET root web.config file because these files are enumerated by the System Writer beginning with Windows Vista with SP1 and Windows Server 2008.
This writer backs up all files that are in the %windir%\system32\inetsrv\config\schema and %windir%\system32\inetsrv\config directories, except for files that are enumerated by the System Writer.
The writer ID for the IIS configuration writer is 2A40FD15-DFCA-4aa8-A654-1F8C654603F6.
Registry Writer
The registry writer is responsible for the Windows registry. Beginning with Windows Vista and Windows Server 2008, the registry writer now performs in-place backups and restores of the registry. On versions of Windows prior to Windows Vista, the registry writer used an intermediate repository file (sometimes called a "spit file") to store registry data.
In Windows Vista and later, the registry writer does not report user hives.
The writer ID for the registry writer is AFBAB4A2-367D-4D15-A586-71DBB18F8485.
COM+ Class Registration Database Writer
This writer is responsible for the contents of the %SystemRoot%\Registration directory. The COM+ catalog is a file in %SystemRoot%\Registration with a name that follows the pattern Rxxxxxxxxxxxx.clb, where xxxxxxxxxxxx is a 12-digit hexadecimal number. There can potentially be multiple such files if COM+ applications have been configured on the computer. The file that contains the current COM+ catalog is the file with the largest value of xxxxxxxxxxxx.
The COM+ class registration database depends on a registry key being backed up and hence needs to be backed up and restored together with the registry.
To restore the COM+ Registration Database, a backup application (requester) must call the ICOMAdminCatalog::RestoreREGDB method.
The writer ID for the COM+ class registration database writer is 542DA469-D3E1-473C-9F4F-7847F01FC64F.
MSSearch Service Writer
This writer exists to delete search index files from shadow copies after creation. This is done to minimize the impact of Copy-on-Write I/O during regular I/O on these files on the shadow-copied volume.
The writer ID for the MSSearch service writer is CD3F2362-8BEF-46C7-9181-D62844CDC062.
WMI Writer
This writer is used for identifying WMI-specific state and data during backup operations. The data includes files from the WBEM repository.
The writer ID for the WMI writer is A6AD5BC2-B509-4E6C-BB19-49D8F43532F0.
Background Intelligent Transfer Service (BITS) Writer
The BITS writer uses the FilesNotToBackup registry key to exclude files from the BITS cache folder. The default cache location is %AllUsersProfile%\Microsoft\Network\Downloader\Cache.
In addition, the BITS writer excludes the following files from backup: the BITS state files (qmgr0.dat and qmgr1.dat), the BITS debug log file, and BITS partially downloaded files.
If the BITS download destination file is an SMB file, the client account must have a trust relationship to the server, or else backups may fail.
The writer ID for the BITS writer is 4969D978-BE47-48B0-B100-F328F07AC1E0.
Automated System Recovery (ASR) Writer
The ASR writer stores the configuration of disks on the system. This writer reports the Boot Configuration Database (BCD) and is also responsible for dismounting the registry hive that represents the BCD during shadow copy creation. The ASR writer must be included in any backups required for bare-metal recovery. For more information about ASR, see Using VSS Automated System Recovery for Disaster Recovery.
The writer ID for the ASR writer is BE000CBE-11FE-4426-9C58-531AA6355FC4.
System Writer
The system writer enumerates all operating system and driver binaries. This writer runs as part of the Cryptographic Services (CryptSvc) service. On Windows Vista and later, the system writer generates a file list that contains the following files.
The restore application is responsible for laying down the files and registry and setting ACLs to match the system shadow copy. The appropriate hard links must also be created for a system state restore to succeed.
The writer ID for the system writer is E8132975-6F93-4464-A53E-1050253AE220.
Shadow Copy Optimization Writer
This writer deletes certain files from volume shadow copies. This is done to minimize the impact of Copy-on-Write I/O during regular I/O on these files on the shadow-copied volume. The files that are deleted are typically temporary files or files that do not contain user or system state.
The writer ID for the shadow copy optimization writer is 4DC3BDD4-AB48-4D07-ADB0-3BEE2926FD7F.
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Build date: 6/18/2009