From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.fusionio.com ([64.244.102.31]:34597 "EHLO mx2.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752558Ab1ACLEI (ORCPT ); Mon, 3 Jan 2011 06:04:08 -0500 Message-ID: <4D21AD7D.7090707@fusionio.com> Date: Mon, 3 Jan 2011 12:05:33 +0100 From: Jens Axboe MIME-Version: 1.0 Subject: Re: Again on IOPS higher than expected in randwrite 4k References: <4D1FFB1B.1010000@shiftmail.org> In-Reply-To: <4D1FFB1B.1010000@shiftmail.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: fio-owner@vger.kernel.org List-Id: fio@vger.kernel.org To: Spelic Cc: fio@vger.kernel.org On 2011-01-02 05:12, Spelic wrote: > Hello, I just subscribed, I noticed that some 20 days ago there was a > thread on "IOPS higher than expected on randwrite, direct=1 tests" on > this ML. It's curious because I subscribed to report basically the > same thing. > > With Hitachi 7k1000 HDS721010KLA330 (maybe the same drives as > Sebastian) I am seeing the same problem of IOPS too high with FIO, up > to 300 IOPS per disk (up to 500 per disk with storsave=performance on > my 3ware but that's probably cheating). I am doing 4k random writes. > > I followed the discussion, I don't really agree with the point at the > end of the discussion, so I'd like to bump this thread again. > > My impression is that these drives do not honor the flush or FUA. > (Directio uses flush or FUA right? you can be sure that data is on the > platters after directio right? Anyway I also set fsync=1 and nothing > changed) O_DIRECT does not imply flush of FUA, I'm afraid. It arguably should use FUA, but currently it does not. -- Jens Axboe