From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753169Ab1A0UYN (ORCPT ); Thu, 27 Jan 2011 15:24:13 -0500 Received: from [216.187.52.7] ([216.187.52.7]:59202 "EHLO mycroft.westnet.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752843Ab1A0UYL (ORCPT ); Thu, 27 Jan 2011 15:24:11 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <19777.54393.645313.900155@quad.stoffel.home> Date: Thu, 27 Jan 2011 15:24:25 -0500 From: "John Stoffel" To: Mark Lord Cc: Justin Piszcz , Stan Hoeppner , Christoph Hellwig , xfs@oss.sgi.com, Linux Kernel , Alex Elder Subject: Re: xfs: very slow after mount, very slow at umount In-Reply-To: <4D419765.4070805@teksavvy.com> References: <4D40C8D1.8090202@teksavvy.com> <20110127033011.GH21311@dastard> <4D40EB2F.2050809@teksavvy.com> <4D418B57.1000501@teksavvy.com> <4D419765.4070805@teksavvy.com> X-Mailer: VM 8.1.1 under 23.2.1 (x86_64-pc-linux-gnu) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>>> "Mark" == Mark Lord writes: Mark> On 11-01-27 10:40 AM, Justin Piszcz wrote: >> >> >> On Thu, 27 Jan 2011, Mark Lord wrote: Mark> .. >>> Can you recommend a good set of mkfs.xfs parameters to suit the characteristics >>> of this system? Eg. Only a few thousand active inodes, and nearly all files are >>> in the 600MB -> 20GB size range. The usage pattern it must handle is up to >>> six concurrent streaming writes at the same time as up to three streaming reads, >>> with no significant delays permitted on the reads. >>> >>> That's the kind of workload that I find XFS handles nicely, >>> and EXT4 has given me trouble with in the past. Mark> .. >> I did a load of benchmarks a long time ago testing every mkfs.xfs option there >> was, and I found that most of the time (if not all), the defaults were the best. Mark> .. Mark> I am concerned with fragmentation on the very special workload Mark> in this case. I'd really like the 20GB files, written over a Mark> 1-2 hour period, to consist of a very few very large extents, as Mark> much as possible. Mark> Rather than hundreds or thousands of "tiny" MB sized extents. I Mark> wonder what the best mkfs.xfs parameters might be to encourage Mark> that? Hmmm, should the application be pre-allocating the disk space then, so that the writes get into nice large extents automatically? Isn't this what the fallocate() system call is for? Doesn't MythTV use this? I don't use XFS, or MythTV, but I like keeping track of this stuff. John