====== ISSUE: VSS_E_FLUSH_WRITES_TIMEOUT (MS SQL database backup in VSS mode) ====== Article ID: 8081 \\ Reviewed: 22/06/2020 \\ Product Version: CloudBacko Pro : 4.1.0.0 or above \\ OS: Windows ===== Problem Description ===== When performing a MS SQL server database backup in VSS backup mode, the following error message is received in the backup report:

No.	Type	Timestamp	Log
*	info	...	...
*	erro	YYYY/MM/DD hh:mm:ss	[VSSDatabaseExpt] VSS_E_FLUSH_WRITES_TIMEOUT
*	...	...	...

===== Cause ===== The message is returned by the MS SQL VSS writer, indicating that the MS SQL VSS writer was unable to create a VSS snapshot of the database(s) within the default time limit due to high disk activities on the server. ===== Resolution ===== To resolve the issue:

Check if there is other I/O intensive application(s) that is running on the client computer at the time of the backup.

Try adjusting the backup schedule to another time when disk usage is low.

Check on the VSS writers:

Open an Administrative command prompt and enter the following command:

vssadmin list writers

This should output a list of writers and their status, they should all be reported as stable.

If there is writer listed at unstable, re-register the Volume Shadow Copy Service by following the instructions below:
- In an administrative command prompt, browse to ${CloudBacko-Install-Home}\bin
- Execute the 'RegisterVSS.bat' batch file.
- Reboot the machine.

Ensure that left-over snapshots are cleaned up:

Enter the following command in an elevated command prompt:

vssadmin delete shadows /all

This will clean up all VSS snapshots.

Defect operating system may often accumulate hundreds of VSS snapshots that persist in the system and cause Windows to become un-responsive.

In some case, you may not be able to delete the VSS snapshots with the above command. Perform the following instead:

To decrease the maximum shadow storage size, enter the following command in an elevated command prompt:

vssadmin resize ShadowStorage /For=C: /On=C: /MaxSize=300MB

If there is no VSS writer error displayed, but the system is not creating a new VSS snapshot, increase the max shadow storage size on the system instead.

To increase the maximum shadow storage, enter the following command in an elevated command prompt:

vssadmin resize ShadowStorage /For=C: /On=C: /MaxSize=10GB

===== Keywords ===== mssql, sql, ms, vss, timeout, flush, disk, activity, VSS_E_FLUSH_WRITES_TIMEOUT, VSS_E_FLUSH, WRITES_TIMEOUT