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 q3AKiTVe207845 for ; Tue, 10 Apr 2012 15:44:29 -0500 Received: from greer.hardwarefreak.com (mo-65-41-216-221.sta.embarqhsd.net [65.41.216.221]) by cuda.sgi.com with ESMTP id hst4PSnHEhKd3IBd for ; Tue, 10 Apr 2012 13:44:29 -0700 (PDT) Message-ID: <4F849BAE.6070901@hardwarefreak.com> Date: Tue, 10 Apr 2012 15:44:30 -0500 From: Stan Hoeppner MIME-Version: 1.0 Subject: Re: XFS: Abysmal write performance because of excessive seeking (allocation groups to blame?) References: <20120405213740.GA22824@infradead.org> <201204072057.38286.Martin@lichtvoll.de> In-Reply-To: Reply-To: stan@hardwarefreak.com List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: quoted-printable Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Stefan Ring Cc: Christoph Hellwig , xfs@oss.sgi.com On 4/10/2012 9:02 AM, Stefan Ring wrote: >> And is XFS aligned to the RAID 6? >> >> What does xfs_info display on it? > = > Yes, it=92s aligned. > = > meta-data=3D/dev/mapper/vg_data-lvhome = Is the LVM volume aligned to the RAID stripe? Is their a partition atop the RAID LUN and under LVM? Is the partition aligned? Why LVM anyway? > isize=3D256 agcount=3D4, agsize=3D732= 33656 blks > =3D sectsz=3D512 attr=3D2 > data =3D bsize=3D4096 blocks=3D292934624, ima= xpct=3D5 > =3D sunit=3D8 swidth=3D32 blks > naming =3Dversion 2 bsize=3D4096 ascii-ci=3D0 > log =3Dinternal bsize=3D4096 blocks=3D143040, versio= n=3D2 > =3D sectsz=3D512 sunit=3D8 blks, lazy-co= unt=3D1 > realtime =3Dnone extsz=3D4096 blocks=3D0, rtextents= =3D0 > = > I changed the stripe size to 32kb in the meantime. This way, it > performs slightly better. The devil is always in the details. Were you using partitions and LVM with the RAID1 concat tesing? With the free space testing? I assumed you were directly formatting the LUN with XFS. With LVM and possibly partitions involved here, that could explain some of the mediocre performance across the board, with both EXT4 and XFS. If one wants maximum performance from their filesystem, one should typically stay away from partitions and LVM, and any other layers that can slow IO down. -- = Stan _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs