From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Sun, 16 Dec 2007 15:31:43 -0800 (PST) Received: from larry.melbourne.sgi.com (larry.melbourne.sgi.com [134.14.52.130]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with SMTP id lBGNVUbr026681 for ; Sun, 16 Dec 2007 15:31:34 -0800 Date: Mon, 17 Dec 2007 10:31:27 +1100 From: David Chinner Subject: Re: Fedora 8.0.1 XFS Tune on HW RAID for Max Write Throughput? Message-ID: <20071216233127.GY4612@sgi.com> References: <1197653927.3841.1226620089@webmail.messagingengine.com> <4764AB08.7040608@sandeen.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4764AB08.7040608@sandeen.net> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Eric Sandeen Cc: Alex Madarasz , xfs@oss.sgi.com On Sat, Dec 15, 2007 at 10:35:20PM -0600, Eric Sandeen wrote: > Alex Madarasz wrote: > > We're building a new Fedora 8.0.1 Linux system to stream data from a > > 250Msps ADC to disk, and want to start tuning the system configuration > > for maximum XFS write performance. To date, without any significant > > effort at tuning our Fedora 7 dev system, we're seeing 250MBps write > > with 8-bit samples and ~ 300MBps write with 16-bit samples. We want to > > push the tuning as far as we can go with this architecture before we > > start looking at other hardware options. Looking at various other > > tuning pages on the Web finds few that are interested in maxing out > > sequential writes to very large arrays while using SAS HW RAID with big > > fast SAS drives too. > > ... > > > XFS Tuning Options? > > > > - HW RAID0: > > - Array/logical disk HW RAID stripe size? > > At any rate you'll want to match xfs's geometry with the raid geometry. > > > - Cache enabled (some reports that cache s/b turned off?)? > > If it's battery-backed cache, leave it on, and disable barriers in xfs > (it's a mount option) > > > - xfs mkfs / mount options? > > David mentioned these before as a generic place to start: > > # mkfs.xfs -f -l lazy-count=1,version=2,size=128m -i attr=2 -d agcount=4 > > # mount -o logbsize=256k > > and that those would be upcoming new defaults for mkfs. > > 4 ags may not be what you want for a ~2T filesystem. Right - the 4 AG tuning is effectively for single disk configurations to limit parallelism and therefore keep seeks between AGs down. When you have multiple disks, the [new] mkfs defaults should be just fine (i.e. just drop the agcount suggestion). Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group