I have a CentOS 6 host system running a CentOS 6 KVM guest and the
guest seems to get about 5x slower disk throughput than the host:
host $ sudo dd of=/dev/datavol/disk1 if=/dev/zero bs=1M oflag=direct count=5
5+0 records in
5+0 records out
5242880 bytes (52 GB) copied, 150.36 s,
* Brian J. Murrell br...@interlinx.bc.ca [2011-12-15 15:28]:
I have a CentOS 6 host system running a CentOS 6 KVM guest and the
guest seems to get about 5x slower disk throughput than the host:
host $ sudo dd of=/dev/datavol/disk1 if=/dev/zero bs=1M oflag=direct
count=5
5+0 records
On 11-12-15 10:47 AM, Stefan Pietsch wrote:
Did you try to set the cache of the virtio disk to none?
I didn't. It was set at default in virt-manager and I suppose I just
assumed that default would be reasonable.
Changing to none has had a good effect indeed:
host $ ssh guest dd of=/dev/vdb
On Thu, 2011-12-15 at 11:55 -0500, Brian J. Murrell wrote:
So, about 2/3 of host speed now -- which is much better. Is 2/3 about
normal or should I be looking for more?
aio=native
Thats the qemu setting, I'm not sure where libvirt hides that.
--
Sasha.
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On Thu, Dec 15, 2011 at 07:16:22PM +0200, Sasha Levin wrote:
On Thu, 2011-12-15 at 11:55 -0500, Brian J. Murrell wrote:
So, about 2/3 of host speed now -- which is much better. Is 2/3 about
normal or should I be looking for more?
aio=native
Thats the qemu setting, I'm not sure where
On 11-12-15 12:27 PM, Daniel P. Berrange wrote:
On Thu, Dec 15, 2011 at 07:16:22PM +0200, Sasha Levin wrote:
On Thu, 2011-12-15 at 11:55 -0500, Brian J. Murrell wrote:
So, about 2/3 of host speed now -- which is much better. Is 2/3 about
normal or should I be looking for more?
aio=native
- Message from Brian J. Murrell br...@interlinx.bc.ca -
Date: Thu, 15 Dec 2011 14:43:23 -0500
From: Brian J. Murrell br...@interlinx.bc.ca
Subject: Re: 5x slower guest disk performance with virtio disk
To: kvm@vger.kernel.org
Cc: Sasha Levin levinsasha...@gmail.com
