[pve-devel] KVM Live Backup performance

[Eric Blevins]

> Besides, live backup uses the same IO thread as KVM, so it looks like using
> one thread (with aio) perform less than using 2 thread.
> But this can also be an advantage if you run more than one VM. Or you can backup
> multiple VM at same time.
>
>
I agree, limiting IO from the VM during backup can have advantages.
On the flip side loosing 50% of the IO bandwidth in a database or mail 
spool VM can be a significant problem.

If storage is really fast then IO in the VM is already limited by KVM, 
limiting it even more has no advantage.