From: Wolfgang Hennerbichler <wolfgang.hennerbichler@risc-software.at>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: <kvm@vger.kernel.org>
Subject: Re: kvm + ceph performance issues
Date: Mon, 11 Mar 2013 10:45:48 +0100 [thread overview]
Message-ID: <513DA7CC.50208@risc-software.at> (raw)
In-Reply-To: <20130308083549.GA8810@stefanha-thinkpad.redhat.com>
On 03/08/2013 09:35 AM, Stefan Hajnoczi wrote:
> Please try using virtio-blk instead of IDE.
there is no difference if I use virtio-blk.
> If the guest still jerks try using the Linux rbd block driver instead of
> QEMU -drive rbd:. I haven't used Ceph much but there should be
> documentation on attaching a RADOS block device to your Linux host.
> Tell QEMU to use the RADOS block device like a regular file (you are now
> using the kernel driver instead of QEMU code to talk to the Ceph
> cluster).
This doesn't work yet on the linux-kernel with format 2 images. Format 2
is capable of read/write snapshots and cooler cloning-stuff. I need this
for backup-reasons.
> Please let us know the outcome. If you find that virtio-blk does not
> make much difference but using the kernel rbd driver does, then this
> suggests there is a bug in QEMU's block/rbd.c.
I'm pretty sure there is, other ceph users reported the same problems
that I've found. The ceph developers are looking into it.
> Stefan
Wolfgang
prev parent reply other threads:[~2013-03-11 9:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-07 11:57 kvm + ceph performance issues Wolfgang Hennerbichler
2013-03-08 8:35 ` Stefan Hajnoczi
2013-03-11 9:45 ` Wolfgang Hennerbichler [this message]
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