I recently migrated/upgraded from vCenter 6.5U2 to 6.7u1. Backup, as well as replication of vCSA fails on Hard Disk 12 & 13. I did apply the Update3a Hotifx. First it fails with "unable to hot add target disk, failing over to network mode..". It will take over an hour and half before completely failing.
11/7/2018 7:08:24 AM :: Error: VDDK operation timed out: Open
Failed to open disk for read.
Failed to upload disk.
Agent failed to process method {DataTransfer.SyncDisk}.
Restarted the Veeam VM (not vCSA) and even deleted the backup/replica of vCSA with no luck. Any ideas?
6.7 Update 1
Not currently supported.
To be supported with the release of Veeam Backup & Replication 9.5 Update 4.
For more information, please see KB2784 and this forum thread.
I know it's not officially supported as of yet. I did apply the temporary registry fix listed in the sticky to allow it to backup other VM's. Guess we'll wait for Update 4 to be able to fully backup vCSA 6.7U1.
If you can’t get it sorted - vcsa has native backup, you can use that as an alternative option until you get it sorted. Also check out the 6.7u1 thread in the forums - may have some useful information.
I saw similar issues after I upgraded/migrated a client to vCSA 6.7.0d (not U1), using VBR 9.5U3a with the VDDK hotfix applied. Disk 13 of the vCSA would consistently fail to back up, with this same timeout error.
I didn't pursue it further, because in this case I decided to eliminate hot-add backups entirely by configuring backup from storage snapshots.