Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver

[Dietmar Maurer]

> > We previously used LVM and run backup with 'idle' IO priority (CFQ) to avoid
> such behavior.
> >
> > But qemu does not provide an IO queue where we can set scheduling
> priorities?
> 
> QEMU block jobs support rate-limiting.  Set it to 10-20% of the disk's 
> throughput
> and the slowness should go away but the backup takes longer.

Sorry, but I don't want to set a rate limit. I want to set an IO priority - 
this is something different.
My solution does not delay the backup.