From: Virtbie <virtbie@shiftmail.org>
To: "'KVM-ML (kvm@vger.kernel.org)'" <kvm@vger.kernel.org>
Subject: Re: Virtual drives performance
Date: Wed, 07 Sep 2011 16:38:44 +0200 [thread overview]
Message-ID: <4E6781F4.7060807@shiftmail.org> (raw)
In-Reply-To: <4E669DD6.5010805@o2.pl>
On 09/07/11 00:25, TooMeeK wrote:
>
> Next, I've tried following combinations with virt-manager 0.8.4 (from
> XML of VM):
> 1.on Debian VM with virtio drivers for both storage and NIC:
> <disk type='block' device='disk'>
> <source dev='/dev/md3'/>
> <target dev='vdb' bus='virtio'/>
> partition type used in guest: EXT4
> result: poor performance, 9-10MB/s sequentional copy via SMB
> 2.on Debian VM with virtio drivers:
> <disk type='block' device='disk' cache='writeback'>
> <source dev='/dev/md3'/>
> <target dev='vdb' bus='virtio'/>
> partition type used: EXT4
> result: poor performance, 10-15MB/s sequentional copy via SMB
> 3.Direct attached partition to FreeBSD VM without virtio support
> (e1000 NIC and SCSI disk):
> <disk type='block' device='disk' cache='writeback'>
Shouldn't have you used cache=none when using virtio?
http://www.linux-kvm.org/page/Tuning_KVM
how is that performance with cache none?
Also note that when you don't specify it, I think the default is not
none. Maybe it is writethrough, I don't remember.
prev parent reply other threads:[~2011-09-08 0:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-06 22:25 Virtual drives performance TooMeeK
2011-09-07 5:50 ` martin f krafft
2011-09-07 7:52 ` Stefan Hajnoczi
2011-09-07 9:46 ` Asdo
2011-09-07 14:38 ` Virtbie [this message]
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