Challenge
Transform operations of a large file located on Windows Server 2012 and 2012 R2 deduplicated volume are failing with an error:
“Error: Client error The requested operation could not be completed due to a file system limitation Failed to flush file buffers. File: Filename.vbk”
Cause
Veeam is not able to write any data to the affected file because of a NTFS limitation.
Manual un-deduplication (Expand-DedupFile) of the this file also fails with the same error.
Solution
Backup repository must be located on a volume formatted with the large FRS using the command “Format <Drive:> /FS:NTFS /L”
Workaround:
1. Disable Windows deduplication
2. Un-dedupe backup files: copy backup files to a temporary folder, delete original backup files and move copied files back to the original location.
3. Disable NTFS compression on backup repository volume.
More Information
This issue is resolved in Windows Server 2012(R2), however formatting with the large FRS using the command “Format <Drive:> /FS:NTFS /L is still needed.
Important: the command Format <Drive:> /FS:NTFS /L erases all data from the drive.
Additional information regarding suggested configuration of Server 2012 dedupe for backup storage can be found in this article: http://technet.microsoft.com/en-us/library/dn891438.aspx
Please note: reformating the volume with /L flag usually helps, but you can still get the same error message later, you can still hit limitation and 4096 Bytes Per FileRecord Segment will not be enough