Hot Add Behavior

[ddockter]

I have a VM with it's disks on a NFS datastore which Veeam backs up using hot add. Last week I added a new disk to that VM. The new disk is on a local datastore which Veeam does not have access to. What I expected to happen during the Veeam backup was for the disks on the NFS datastore to still be backed up using hot add, and for the new disk to be backed up over the LAN. But what is happening is Veeam backs all disks up over the LAN. I see the below messages during the backup.

Hot add is not supported for this disk, failing over to network mode...
Hot add is not supported for this disk, failing over to network mode...
Hot add is not supported for this disk, failing over to network mode...

[Helqasem]

Is it an IDE disk? Make sure disk is SCSI and not-IDE. SCSI hot-add does not work on IDE disks.

[ddockter]

They are all SCSI on the same SCSI controller. Would it make a difference if I added the new disk on the local datastore to a 2nd SCSI controller instead of to the same SCSI controller as the disks on the NFS datastore? Would Veeam then be able to backup up the NFS datastore disks via hot add and the local datastore over the network? Just to clarify my Veeam VM is on host ESX2 and the VM being backed up is on host ESX3. The disk I added to the VM is on a local datastore on ESX3.

[Vitaliy S.]

Hi Doug,

Actually you've just faced a known limitation of vStorage API when it is not possible to partially use hot add backup mode to process a VM. The reason for failing over to network mode is simple - during HotAdd backup mode vStorage API tries to hot add all disks of the backed up VM. If one of the disks fails to hot add, all other VM disks are switched to network processing mode too, even though they can be accessed directly.

If you want to continue processing this VM in the Hot Add mode, you should relocate this disk to NFS storage.

Thanks!

[ddockter]

I was afraid that would be the answer. Thanks.