[pve-devel] KVM Live Backup performance

[Alexandre DERUMIER]

>>The tests form Eric only do reads (there is no single write involved). 
Oh, I miss that.

I think it should be a qemu problem, as only difference is that

 with lvm snapshot backup,

backup reads are done directly from disk

and with qemu backup

reads are done through qemu

Maybe qemu has more overhead to read disk, or maybe they are some slowdown when guest need to read disk, and backup job need to read it too.

Also, does the backup have a difference of speed if vm use ide or virtio drives ?




----- Mail original ----- 

De: "Dietmar Maurer" <dietmar at proxmox.com> 
À: "Alexandre DERUMIER" <aderumier at odiso.com>, "Eric Blevins" <eric at netwalk.com> 
Cc: pve-devel at pve.proxmox.com 
Envoyé: Mardi 26 Novembre 2013 08:25:18 
Objet: RE: [pve-devel] KVM Live Backup performance 

> Hi, this is because with new backup, 
> 
> each new write in the vm during the backup, is copied to backup storage and to 
> the vm. 

The tests form Eric only do reads (there is no single write involved).