> > 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.
