In the previous error messages, pay close attention to the writer, the protocol that is used for the connection, and the error message that is returned. These types of connection issues may occur for the following reasons:
The SQL writer handles the validation, closing of file handles, etc. The SQL writer attaches the database and does crash recovery if needed. Between these two phases, the backup application is responsible for moving the relevant data around underneath SQL. Restore Initialization During the initialization phase of a restore, the requestor needs to have access to the stored Backup Components Documents.
The Backup Component Document that is generated during the backup operation, is stored as part of the backup data. The backup application needs sqlserverwriter service name for port pass this data back to the VSS framework. The SQL writer obtains access to this data at the beginning of the restore process.
Prepare for Restore In preparing for a restore, a requestor uses the stored Backup Components Documentto determine what is to be restored and how. The requestor will select the components to be restored and set appropriate restore options as needed. Note If a backup application intends to apply differential or log backups on top of the current restore operation i.
The SQL writer will examine the supplied Backup Component Documentto identify the appropriate databases, deleting any additional files created since the backup time.
It also checks disk spaces and closes any opened database file handles so that the requestor can copy the needed data during the Restore phase. This phase allows any early error conditions to be detected before the requestor does the actual file copying. SQL Server will also put the database in restoring state.
From this point on, the database cannot be started until a successful restore. Restore Files This is purely a requestor-specific action. It is the responsibility of the requestor backup application to copy the needed database files or copy relevant ranges of data for differential restores to the appropriate places.
The SQL writer is not involved in this operation. Cleanup and Termination Once all the data is restored to the right places, a call from a requestor notifying that the restore operation has been completed IvssBackupComponents:: The SQL writer at this point will do the Redo phase of crash recovery.
If recovery is not requested i.
Backup In a noncomponent-based backup, the SQL writer implicitly selects databases by using the list of volumes in the snapshot set. The writer checks for torn databases, raising an error if found. A torn database is one in which a subset of files is selected by the list of volumes.
Roll forward differential or log restores after a restore is not supported through the SQL writer. Restore The requestor restores database s that have been backed up in noncomponent-based mode.
Note that such restores cannot be followed up by a rollforward restore, such as log restore or differential restore. The files are copied in place and then the database s attached.
All this happens outside the scope of the SQL writer. Backup In a component-based backup, all backing volumes for selected databases should be included in the volume snapshot set. Otherwise, the SQL writer will detect torn databases with backing volumes outside the snapshot set and fail the backup.
A full backup backs up database data and all the log files necessary to bring the database up to a transactionally consistent state at restore time. This may be due to the fact that there is no metadata to facilitate the rollforward or, in some cases, rollforwards are not needed.
This section covers these two situations briefly.
Metadata exist but no additional rollforward is needed The requestor restores database s that have been backed up in component-based mode but no rollforwards are requested.
In this case SQL Server will perform crash recovery on the database as part of restore. Full restore with additional rollforwards The requestor can issue a restore specifying the SetAdditionalRestores true option.
This option indicates that the requestor is going to follow up with more rollforward restores such as log restore, differential restore etc. This instructs SQL Server not to perform the recovery step at the end of the restore operation.
This is only possible if the writer metadata was saved during the backup and is available to the SQL writer at the time of the restore.You can use the list below to find the service that corresponds to the VSS Writer in question.
Restart the corresponding windows services for the writers that are down. Use the vssadmin list writers command again to show if the vss writer is now in a stable state. Check that the SQL Server VSS Writer Service is added to the sysadmin role in the SQL Server Management Console. Run vssadmin list writers again.
If the SQL Server Writer is now in the Stable state, you found the issue. How to Check Volume Shadow Copy Services Driver State Last updated on If you encounter errors during backup initialization of Microsoft Server or R2, or Small Business Server (SBS) , you may have misconfigured or disabled .
SQL Server connectivity and Volume Shadow Copy Service For this month's column, Suresh Kandoth will address Microsoft SQL Server connectivity and Volume Shadow Copy Service (VSS). Suresh is an escalation engineer with the SQL Server Support team. We will discuss the MSDEWriter writer and the SqlServerWriter writer in this article.
The Volume Shadow Copy Service (VSS) captures and copies stable images for backup on running systems, particularly servers, without unduly degrading the performance and stability of the services they provide. SqlServerWriter. The SqlServerWriter writer is a VSS Writer for SQL Server.
SqlServerWriter is included with SQL Server Sep 01, · SQL writer service can be enabled by marking this service as “Automatic”. Writer name - L"SqlServerWriter" A requestor may need to restore an SQL database with a new name, especially if the database is to be restored side by side with the original database.