From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752360Ab1JLC7U (ORCPT ); Tue, 11 Oct 2011 22:59:20 -0400 Received: from tn-76-7-162-101.sta.embarqhsd.net ([76.7.162.101]:57871 "EHLO animx.eu.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751796Ab1JLC7U (ORCPT ); Tue, 11 Oct 2011 22:59:20 -0400 Date: Tue, 11 Oct 2011 22:59:18 -0400 From: Wakko Warner To: linux-kernel@vger.kernel.org Subject: Re: Slow write performance with mpt2sas Message-ID: <20111012025918.GA16695@animx.eu.org> Mail-Followup-To: linux-kernel@vger.kernel.org References: <20111012002556.GA32495@animx.eu.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111012002556.GA32495@animx.eu.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Wakko Warner wrote: > I've noticed that my SAS9212-4i4e is having write issues. I have a raid5 of > 4 2tb seagate green drives and a raid5 of 3 300gb seagate 15k sas drives. > Write performance on the green drives is fairly poor. The riad4 of 4 disks > has a write performance of about 6-10mb/sec. My onboard sas controller > (1068e chip IT mode) does not have this issue (I'm using raid6 on 8 of the > same model green drives). > > Write performance on the 15k drives in raid 5 was 140mb/sec (4gb volume). Sorry, this appears to be a KVM issue. I had forgotten that I was using this under KVM. Adding cache=writeback fixed my problems (Also note, my load before this went to >35 when writing, now it's no higher than about 9)