From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Better to use iSCSI on host or guest? Date: Tue, 14 Jun 2011 11:18:35 +0300 Message-ID: <4DF7195B.3090606@redhat.com> References: <4DF63BEC.2020809@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm To: Emmanuel Noobadmin Return-path: Received: from mx1.redhat.com ([209.132.183.28]:37778 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753257Ab1FNISk (ORCPT ); Tue, 14 Jun 2011 04:18:40 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 06/13/2011 10:00 PM, Emmanuel Noobadmin wrote: > On 6/14/11, Avi Kivity wrote: > > 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. > > Any suggestions or recommendations as to how/what should I be measuring with? Whatever workload you'll be running on those guests. > So far in trying to determine how bad is the qcow2 disk bottleneck on > my VMs, I've been using dd with dsync and direct options as well as > hdparm which errors out (not sure if this is considered a KVM/virtio > bug?) on the virtio disk after getting a buffered result. > > But these don't seem to be very good tools since it's all sequential > only. I've tried iozone on my home machine but it takes too long per > run; unfortunately this host and its VMs are live and I don't have the > luxury of another full set of hardware to test on. fio is a good tool. -- error compiling committee.c: too many arguments to function