From: Avi Kivity <avi@redhat.com>
To: Emmanuel Noobadmin <centos.admin@gmail.com>
Cc: kvm <kvm@vger.kernel.org>
Subject: Re: Better to use iSCSI on host or guest?
Date: Mon, 13 Jun 2011 19:33:48 +0300 [thread overview]
Message-ID: <4DF63BEC.2020809@redhat.com> (raw)
In-Reply-To: <BANLkTi=00qesWQa4Qyt1jLXMR4LS=NDSXA@mail.gmail.com>
On 06/13/2011 07:05 PM, Emmanuel Noobadmin wrote:
> I'm planning to use iSCSI targets (over gigabit VLANs) for KVM guest
> disks. The question I'm wondering about is whether it's better to md
> (multi-path + mirror) the iSCSI targets on the host, then create LVM
> partitions for the guests. Or to directly md the iSCSI targets within
> the guest.
>
> On one hand I think it would be slower to process the additional
> layers in the guest, but on the other hand, readings seems to indicate
> that the kernel is able to perform better disk i/o if it's aware of
> multiple disks rather than just seeing a single disk.
>
> I've not been able to find any definitive article/data on how these
> might balance out. Would anybody in the list have a good idea which
> way is better in terms of i/o performance?
My gut feeling is to do iscsi in the host. I guess it's best to measure
though. Please post your findings if you do that.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-06-13 16:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-13 16:05 Better to use iSCSI on host or guest? Emmanuel Noobadmin
2011-06-13 16:33 ` Avi Kivity [this message]
2011-06-13 19:00 ` Emmanuel Noobadmin
2011-06-14 8:18 ` Avi Kivity
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