[pve-devel] KVM Live Backup performance

Dietmar Maurer dietmar at proxmox.com
Fri Nov 22 19:20:13 CET 2013

> >> No, it took dd 120 seconds to read 8GB of data when using live backup
> >> and only took 55 seconds when using LVM snapshot backup.
> > OK.
> >
> > But your test dose not issue a single write?
> >
> Right, I mentioned that I had not tested writes yet.
> Live backup had such a significant impact on sequential read inside the VM it
> seemed appropriate to post those results so others can also investigate this.

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.

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