Welcome, if you are looking for support on One Identity products, please visit One Identity Portal.
Backup Failure System Unable to Flush I/O Writes
You experience backup failures on your agent, with the following error displayed.
"Replay.Core.Contracts.Transfer.VssGeneralErrorException: There was a problem with the VSS subsystem on 'xxxxx'. ---> Replay.Agent.Contracts.ShadowCopy.ShadowCopyException: DoSnapshotSet failed with error: 'The system was unable to flush I/O writes. This can be a transient problem. It is recommended to wait ten minutes and try again, up to three times.'"
This error maybe as a result of an issue with the VSS subsystem on the Agent machine caused by VSS not being able to quiesce data to the disk within the VSS timeout window. Potential environmental issues that may cause the problem are:
In Hyper-V environments, this might be due to Hyper-V integration services called Backup for Window Server 2012 R2 Hosts, and the way/speed that the OS releases VSS for the requester (in this case AppAssure software).
Following a possible resolutions to mitigate against environmental issues that can be the cause of the problem:
1. Corruption of the NTFS structure of the disk
c. Ensure that any errors that are found are fixed
2. High fragmentation of the disk
Run the defrag analysis tool on each of the disks. If the fragmentation is found to be greater than 20% then the disk should be defragmented. For disks that are low on free space, running disk defrag may be necessary even when the fragmentation is less than 20%.
3. High IO on the disk
If possible reduce the IO on the disk. If it is not possible to reduce the IO on the disk, then attempt to schedule around it.
3.1 Set the backups to run at a low IO time:
3.2 Stagger the Protection Intervals:
4. No free space on the System Reseve Partition (SRP) and the agent change log is locked
When the SRP is full, there is no free space on this volume for VSS to create a shadow copy. Furthermore, when the AppAssure Agent change log is locked (cannot take posession to delete the file), VSS will timeout as this log file cannot be accessed.
To resolve, uninstall the agent with the "Removeagent settings and change logs" checkbox enabled. Please note, uninstalling the Agent softwall does require a reboot to complete the process. Reinstall the Agent software (second reboot required) and check the SRP's size as free space should exist. Reprotect the Agent and take a new base image.
5. For Hyper-V environments, try disabling any snapshot by Hyper-V, if it is already enabled.
a. Disable the backup feature for the VM. The setting is found on the Hyper V manger under integration services and un-check backup.