Problem: After backing up a VM using the SAN transport mode, the restore of the VM fails to use SAN mode and falls back to using NBD mode. This happens if the VM is deleted after backup. Customers may see Failed to write disk data, VDDK error encountered:
code 1 or VDDK error message is 'Unknown error' in the logs. Restore falls back to NBD transport mode instead of SAN.
No current fix... two possible workarounds:
Workarounds:
1) Use a virtual machine as your backup proxy. This will allow the use of HotAdd transport mode which doesn't exhibit the same problem. This should give performance close to the SAN transport.
- or -
2) Allow fallback to NBD or NBDSSL mode. Though slower on Thick (Eager Zeroed) disks this is actually recommended by VMware as the best performing restore method for Thin and Lazy Zeroed Thick disks(Ref: http://kb.vmware.com/kb/1035096)
