From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id p6J00KXW133790 for ; Mon, 18 Jul 2011 19:00:20 -0500 Received: from mail.sandeen.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 9D54079D90 for ; Mon, 18 Jul 2011 17:00:19 -0700 (PDT) Received: from mail.sandeen.net (sandeen.net [63.231.237.45]) by cuda.sgi.com with ESMTP id 5YXusD5OXXe5XL9S for ; Mon, 18 Jul 2011 17:00:19 -0700 (PDT) Message-ID: <4E24C912.20003@sandeen.net> Date: Mon, 18 Jul 2011 19:00:18 -0500 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: 30 TB RAID6 + XFS slow write performance References: <4E24907F.6020903@johnbokma.com> In-Reply-To: <4E24907F.6020903@johnbokma.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: John Bokma Cc: xfs@oss.sgi.com On 7/18/11 2:58 PM, John Bokma wrote: > Dear list members, > = > A customer of mine is currently struggling with the performance of a > 30 TB RAID6 which uses XFS as the filing system. I am somewhat sure > it's not XFS that's causing the performance issue but my expertise is > not XFS nor RAID; I just wrote the software that after moving to the > larger RAID (from a much smaller one, ~ 3TB, using ext3) suddenly > seems to have a huge drop in write performance. > = > The software I wrote writes many small (50-150K) files in parallel > (100+ processes), thousands of times per hour. Writing a file of > 50-150K now and then seems to take between 30 and 90 seconds, and > more rarely can take over 200 seconds (several times an hour). > = > When all processes are stopped and restarted again the 30-90 seconds > delay start happening when about 16-20+ processes are running. > = > To me this sounds like something has been configured wrong. I already > recommended my customer to find someone who is capable of configuring > the RAID correctly; to me it sounds like a hardware/configuration > issue. > = > Any insights are very welcome. > = > Hardware: card: MegaRAID SAS 9260-16i disks: 14x Barracuda=AE XT > ST33000651AS 3TB (2 hot spares). RAID6 ~ 30TB My first suggestion would be to check the partition alignment on the raid (= if it is partitioned), and be sure it is aligned with the underlying raid g= eometry. And then make sure you give mkfs.xfs the proper geometry as well. After that, does the raid card have a battery-backed write cache? If so, y= ou can safely disable barriers. More info is always good too, for starters what kernel & what xfsprogs vers= ion? What mkfs & mount options? -Eric > Thanks for reading, John > = > _______________________________________________ xfs mailing list = > xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs > = _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs