Challenge
A backup or backup copy job writing to a Quantum DXi deduplication appliance is failing with:
Error: File does not exist. File: [\\dxi01\veeam\backup_job_1\backup_job_12016-06-13T210000.vbk]. Agent failed to process method {Stg.OpenRead}.
The initial error may or may not be visible in the statistics or the HTML report, but it is present in the debug logs:
error: boost::filesystem::rename: The specified network name is no longer available
Cause
By default, Windows SMB (CIFS) sessions time out after 60 seconds. The Quantum DXi may not respond to rename requests within 60 seconds if the file to be renamed is being processed by a deduplication job. When Windows closes the SMB connection, it reports the error message “The specified network name is no longer available.”
Veeam Backup & Replication assumes that when a rename request fails, the file is not renamed. However, the Quantum DXi does rename the file.
Solution
To resolve the immediate problem, manually rename the *.vbk file to match the file name in the error message. If there are multiple *.vbk files, be careful to rename the correct one; if it is unclear, please contact Veeam Support for assistance.
To prevent the error from re-occurring, either change the backup method to one that does not rename files, or extend the timeout on the gateway server(s).
Backup Methods
For backup jobs, use forward incremental with active full backups.
Forward incremental with transform to rollbacks, forward forever incremental, and reverse incremental backups all rename *.vbk files after merging new data into the full backup. Forward incremental with synthetic full backups will not rename *.vbk files, but performance is usually much better with active full backups.
For backup copy jobs, enable the Read the entire restore point from source instead of synthesizing it from increments option. If this option is not enabled, *.vbk files will be renamed.
More info is available in User Guide:
Backup Methods
Retention Policy
Backup Copy Methods
Timeout
To increase the SMB session timeout, create this registry value on the gateway server:
Location: HKLM\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters\
Value name: SessTimeout
Value type: DWord
Decimal values as low as 300 (5 minutes) have been sufficient for some customers; in other cases, extending the timeout to 3600 (1 hour) was required. A reboot is required.
If using automatic gateway selection, you may need to make this change on all Windows servers in the backup infrastructure.
More Information
An active full backup will also work around the immediate problem, but this will cause retention policy to fail for older files. That is, these files must be deleted manually when they are no longer needed.
Deduplication Appliance Best Practices