[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands |
Date: |
Thu, 7 Mar 2013 10:05:41 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Wed, Mar 06, 2013 at 02:42:57PM +0000, Dietmar Maurer wrote:
> > > > Maybe you'd better use a different output format that doesn't
> > > > restrict you to 64k writes.
> > >
> > > The output format is not really the restriction. The problem is that
> > > an additional IPC layer add overhead, an d I do not want that (because it
> > > is
> > totally unnecessary).
> >
> > I missed the reason why you cannot increase the block size.
>
> When we run backup, we need to read such block on every write from the guest.
> So if we increase block size we get additional delays.
Don't increase the bitmap block size.
Just let the block job do larger reads. This is the bulk of the I/O
workload. You can use large reads here independently of the bitmap
block size.
That way guest writes still only have a 64 KB read overhead but you
reduce the overhead of doing so many 64 KB writes from the backup block
job.
Stefan
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, (continued)
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Kevin Wolf, 2013/03/04
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Dietmar Maurer, 2013/03/04
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Stefan Hajnoczi, 2013/03/06
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Dietmar Maurer, 2013/03/06
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Kevin Wolf, 2013/03/06
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Dietmar Maurer, 2013/03/06
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Kevin Wolf, 2013/03/06
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Dietmar Maurer, 2013/03/06
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Kevin Wolf, 2013/03/07
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Dietmar Maurer, 2013/03/07
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands,
Stefan Hajnoczi <=
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Dietmar Maurer, 2013/03/07
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Stefan Hajnoczi, 2013/03/08
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Dietmar Maurer, 2013/03/08
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Stefan Hajnoczi, 2013/03/08
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Dietmar Maurer, 2013/03/08
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Stefan Hajnoczi, 2013/03/10
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Dietmar Maurer, 2013/03/10
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Stefan Hajnoczi, 2013/03/10
- Re: [Qemu-devel] [PATCH v4 3/6] add backup related monitor commands, Dietmar Maurer, 2013/03/09