Case #07884920 - Backups failing using VSA13 using Windows-backup proxy with Direct SAN

[chrisflyckelen]

Hey everyone,

I'd like to share this case to figure out whether anyone else is facing the same issue.

I’m working on a project that’s early-adopting Version 13 using VSA. No problems so far, as it was a greenfield installation. The backup server was deployed using the OVA template in a VMware vSphere environment. There is also a Windows-based backup proxy connected to the production storage via Fibre Channel. The proxy is Windows-based because Fibre Channel isn’t supported by the new infrastructure appliance ISO yet. It was added to VBR using a deployment kit with certificate authentication.

The backup repository target is an S3 repository. Important to note: all backup infrastructure components (VBR server, backup proxy, and repository) are on the same network. The VMware vSphere infrastructure is on a different network.

During initial tests with a long-running backup job protecting 31 TB of production data, the backup fails with errors such as:
11.11.2025 15:05:13 Failed: Job has failed unexpectedly
11.11.2025 14:40:21 Failed: Error: End of file [asio.misc:2] Failed to upload disk '>' (End of file [asio.misc:2]) (Failed to upload disk '>')

While investigating, we were able to rule out the usual suspects like firewall issues, networking, resource limitations, SAN zoning, and so on. For testing, a V12 backup server was deployed and the backup proxy was moved to the V12 VBR. Same backup target, same production storage, same VM… drumroll — the job completed successfully.

Is anyone else seeing the same or similar issues? Were you able to solve it? If yes, I’d appreciate hearing what the root cause was.

Thanks,
Christian