From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stan Hoeppner Subject: Re: very slow file deletion on an SSD Date: Sat, 26 May 2012 14:56:54 -0500 Message-ID: <4FC13586.8060408@hardwarefreak.com> References: <4FBF60D1.80104@gmail.com> Reply-To: stan@hardwarefreak.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4FBF60D1.80104@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Joe Landman Cc: xfs@oss.sgi.com, linux-raid List-Id: linux-raid.ids On 5/25/2012 5:37 AM, Joe Landman wrote: > Hi folks: Hi Joe, I may be all wet here, but this is the only thing that jumped out at me: > meta-data=/dev/md20 > data = sunit=8 swidth=56 blks > log =internal sunit=8 blks 8*56KB (or 7*64KB) = 448KB write out > [root@siFlash ~]# mdadm --detail /dev/md20 > /dev/md20: > Version : 1.2 > Raid Devices : 8 > Layout : left-symmetric > Chunk Size : 32K 7*32KB = 224KB stripe size > All this said, deletes from this unit are taking 1-2 seconds per file ... > Anything obvious that we are doing wrong? Other than your XFS writeout being apparently twice the size of your RAID stripe, nothing else stands out that I can see. I'm not a block layer expert. And since mkfs.xfs came up with 448KB, apparently this should be fine. However, everything in the literature, and the experts on this list, tells us to always precisely align XFS to the RAID stripe. That doesn't seem to be the case here. -- Stan