From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id A2D4F7F50 for ; Tue, 3 Nov 2015 06:19:07 -0600 (CST) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay2.corp.sgi.com (Postfix) with ESMTP id 72FAA304043 for ; Tue, 3 Nov 2015 04:19:04 -0800 (PST) Received: from firestarter.dermichi.com (firestarter.dermichi.com [194.177.153.153]) by cuda.sgi.com with ESMTP id WUnX2wFuSDkH0i6G (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Tue, 03 Nov 2015 04:18:55 -0800 (PST) Received: from noclinksys.net4you.net ([194.177.153.180] helo=[127.0.0.1]) by firestarter.dermichi.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim) (envelope-from ) id 1ZtaY9-0006bx-Ul for xfs@oss.sgi.com; Tue, 03 Nov 2015 13:18:53 +0100 From: Michael Weissenbacher Subject: Is it possible to change sunit of log section post-mkfs Message-ID: <5638A62D.1020802@dermichi.com> Date: Tue, 3 Nov 2015 13:18:53 +0100 MIME-Version: 1.0 List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com Hi! I have a XFS file system which lies on a 10-disk RAID-6 device that was created with Chunk Size = 1MiB. On mkfs.xfs time this was - as far as i know - specified with "-d su=1m,sw=8". xfs_info shows the following: meta-data=/dev/sdb1 isize=256 agcount=15, agsize=268435200 blks = sectsz=512 attr=2 data = bsize=4096 blocks=3905945088, imaxpct=5 = sunit=256 swidth=2048 blks naming =version 2 bsize=4096 ascii-ci=0 log =internal bsize=4096 blocks=521728, version=2 = sectsz=512 sunit=8 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 Interestingly, the sunit value of the log seems to be incorrect - as it should be 256 too, like the sunit value of the data. I am pretty sure the reason is that the log sunit cannot be 256 blks (=1024KiB) and because of this mkfs.xfs did fall back to the default of 8 blks (=32KiB). I found evidence of this in the following thread: http://oss.sgi.com/archives/xfs/2012-06/msg00431.html What i want to achieve is to set the log sunit to the maximum possible of 64 blks (=256KiB). - Is that even possible without doing mkfs.xfs (and losing all data)? - Would it be an improvement performance-wise? - Would changing to an external log help? tia, Michael _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs