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 A02A87FCB for ; Tue, 3 Nov 2015 13:11:55 -0600 (CST) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay2.corp.sgi.com (Postfix) with ESMTP id 92215304039 for ; Tue, 3 Nov 2015 11:11:52 -0800 (PST) Received: from ipmail07.adl2.internode.on.net (ipmail07.adl2.internode.on.net [150.101.137.131]) by cuda.sgi.com with ESMTP id 2XU197AnpfKRWE9u for ; Tue, 03 Nov 2015 11:11:46 -0800 (PST) Date: Wed, 4 Nov 2015 06:11:32 +1100 From: Dave Chinner Subject: Re: Is it possible to change sunit of log section post-mkfs Message-ID: <20151103191132.GD19199@dastard> References: <5638A62D.1020802@dermichi.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5638A62D.1020802@dermichi.com> 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: Michael Weissenbacher Cc: xfs@oss.sgi.com On Tue, Nov 03, 2015 at 01:18:53PM +0100, Michael Weissenbacher wrote: > 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). Why? Is there a performance problem with the default setting? Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs