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Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver |
Date: |
Tue, 26 Feb 2013 17:49:02 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Feb 25, 2013 at 03:49:11PM +0000, Dietmar Maurer wrote:
> > > 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.
QEMU is not in a position to implement global scheduling (priorities).
The QEMU process only knows about one guest. If you have multiple
guests on the host an I/O "priority" inside QEMU process A will not take
into account QEMU process B.
Your solution *does* delay backup by 1 ms each iteration :).
Stefan
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, (continued)
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, Dietmar Maurer, 2013/02/21
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, Stefan Hajnoczi, 2013/02/21
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, Dietmar Maurer, 2013/02/25
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, Stefan Hajnoczi, 2013/02/25
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, Dietmar Maurer, 2013/02/25
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, Stefan Hajnoczi, 2013/02/26
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, Dietmar Maurer, 2013/02/26
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, Stefan Hajnoczi, 2013/02/27
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, Dietmar Maurer, 2013/02/27
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, Kevin Wolf, 2013/02/28
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver,
Stefan Hajnoczi <=
- Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver, Dietmar Maurer, 2013/02/26
[Qemu-devel] [PATCH v4 6/6] add vm state to backups, Dietmar Maurer, 2013/02/20
[Qemu-devel] [PATCH v4 1/6] add documenation for new backup framework, Dietmar Maurer, 2013/02/20
[Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Dietmar Maurer, 2013/02/20