Agent failed to process method {ReFs.SetFileIntegrity}.
Challenge
A Backup or Backup Copy job fails with the following error message:
Error: Incorrect function. Agent failed to process method {ReFs.SetFileIntegrity}.
Cause
Solution
This issue has been observed to occur under two different scenarios:
Scenario 1: The Job is Targeting an SMB/CIFS Repository
When an SMB Share repository is added to Veeam Backup & Replication, if that SMB Share advertises that it is capable of certain features, Veeam Backup & Replication will mark the repository as being Fast Clone compatible. While SMB shares are supported for Fast Clone, there are certain specific requirements. In rare cases, Veeam Backup & Replication may assume, based on the reported capabilities of an SMB share, that the SMB share is compatible with Fast Clone when in fact, the underlying storage of the NAS is not actually Fast Clone compatible.
This issue has been observed as occurring most often with Synology devices, though other NAS devices may be affected.
Registry Setting to Disable Fast Clone for SMB
The following registry value force Veeam Backup & Replication to never use Fast Clone with SMB shares.
It must be created on the Veeam Backup Server.
Key Location: HKLM\SOFTWARE\Veeam\Veeam Backup and Replication\
Value Name: UseCifsVirtualSynthetic
Value Type: DWORD (32-Bit) Value
Value Data:
0 = Disable using Fast Clone with SMB Share
1 = Enable using Fast Clone with SMB Shares
Note:
- This value takes effect on the next job run. There is no need to restart the Veeam services.
- This setting will disable Fast Clone functionality for all SMB repositories.
PowerShell Cmdlet to create Registry Value to Disable Fast Clone for SMB
Scenario 2: The Job is Targeting a Windows Repository
When a Windows Repository is added to Veeam Backup & Replication, the software checks if the filesystem is ReFS, and if it is, marks it as being Fast Clone compatible. If for any reason, the underlying filesystem is later changed to NTFS, the jobs targeting that Repository will continue to attempt to use Fast Clone (enable ReFS Integrity Streams).
Resolve the issue by forcing Veeam Backup & Replication to recheck Fast Clone compatibility:
- Edit the Repository.
- Click the Finish button.
After editing the Repository and allowing Veeam Backup & Replication to recheck the filesystem and Fast Clone compatibility, the job will stop attempting to enable ReFS Integrity Streams.
More Information
The registry value below is being documented on this KB as it is often found when researching the error message "Agent failed to process method {ReFs.SetFileIntegrity}." The intent of documenting it here is not to endorse its usage but instead to clarify its purpose and prevent misuse.
This registry value exclusively controls whether Veeam Backup & Replication will attempt to use Fast Clone with Windows Repositories and has nothing to do with SMB/CIFS repositories. It was created for those rare situations where a ReFS-backed repository is in use, and a user does not want Veeam Backup & Replication to use Fast Clone at all.
For the vast majority of situations, this registry value should not have to be created, as Veeam Backup & Replication will only attempt to use Fast Clone if it detects that a ReFS volume has been added as a Windows Repository. As documented in the Solution section above (Scenario 2), simply editing the Windows repository and clicking Finish will cause the Fast Clone capabilities to be re-evaluated.
Key Location: HKLM\SOFTWARE\Veeam\Veeam Backup and Replication\
Value Name: RefsVirtualSyntheticDisabled
Value Type: DWORD (32-Bit) Value
Value Data: [0= Default, 1=Disable Fast Clone]
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