Guest quiescence suspend question

[Jacv]

The guest quiescence under advanced options mentions that with non app aware guests, you can either add a SCSI card and backup as running for a crash consistent backup or suspend the guest.

I assumed this meant that if I suspend non essential guests when backing up, then restoring them would be like resuming (ie they would be at point of time of backup).

Playing with Instant VM recovery has my suspended guest backup (Ubuntu) cold booting like as with a crash consistent backup.

Am i misunderstanding or doing something wrong?

Thanks

[alanbolte]

All backup types will result in a cold boot on restore, because the memory state of the VM is not saved by the backup job.

[Jacv]

All backup types will result in a cold boot on restore, because the memory state of the VM is not saved by the backup job.

So assuming the guest has a SCSI controller to allow continual running while baking up, in what scenario would it be beneficial to suspend the guest if that backup is still crash consistent?

[alanbolte]

To be honest I've never looked at it that closely; I think what happened is that prior to 2012r2, there was no native Hyper-V method for backing up a running VM that didn't support 'online' backup without suspending it, so we invented our own method of crash-consistent backup. In 2012r2, saved state backup was apparently replaced with checkpoint-based backup, so I'm not sure that setting makes much of a difference. I don't remember there ever being a good use-case for saved state backup.

On the other hand, live backup of Ubuntu is supposedly possible on 2012r2 anyway.