error during syncfs: Remote I/O error (os error 121)

[lemen]

I am trying to make a backup of a 7.8Tb machine for the first time but when it finishes after 2 days it gives me this error. On another backup server, as it already has an original backup, it is done in about 30 minutes.

The error it gives me is the following

ERROR: backup finish failed: command error: error during syncfs: Remote I/O error (os error 121)
INFO: aborting backup job
INFO: resuming VM again
ERROR: Backup of VM 100 failed - backup finish failed: command error: error during syncfs: Remote I/O error (os error 121)
INFO: Failed at 2024-06-24 12:12:45
INFO: Backup job finished with errors
TASK ERROR: job errors

Thanks

 

[Chris]

Hi,
seems like your target storage has an issue and fails because the snapshot contents cannot be synced when finalizing the backup. Check your (remote) storage for errors and make sure the storage can handle the load.
See also tunable options on how to sync the chunks which are documented here https://pbs.proxmox.com/docs/storage.html#tuning

 

[VictorSTS]

Alternatively, you may try to sync that backup to the "second" PBS server, then make the backup from PVE.

 

[lemen]

Thanks, I'll try. What do you recommend to mount a single volume with 12 10TB raid disks? XFS? ext4?

 

[Chris]

Thanks, I'll try. What do you recommend to mount a single volume with 12 10TB raid disks? XFS? ext4?

For HDDs, the use of a fast metadata cache is recommended, e.g. a ZFS special device mirror. Recommendations can be found in the documentation, please let me refer you to https://pbs.proxmox.com/docs/installation.html#recommended-server-system-requirements