From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Kus Subject: Increasing maxsect of md devices? Date: Wed, 02 Mar 2011 14:26:02 -0800 Message-ID: <4D6EC3FA.4030809@bartk.us> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hello, This seems contradictory: jo ~ # blockdev --getiomin /dev/md5 524288 jo ~ # blockdev --getioopt /dev/md5 4194304 jo ~ # blockdev --getmaxsect /dev/md5 255 jo ~ # blockdev --getbsz /dev/md5 4096 jo ~ # blockdev --getss /dev/md5 512 jo ~ # Optimal IO size is reported as 4MB (and that is indeed the stripe size), but maximum sectors per request is only 128kB? How can software do optimal 4MB IOs with the maxsect limit? Does XFS care about this limit? --Bart