From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Guntsche Subject: Re: Severe slowdown with LVM on RAID, alignment =?UTF-8?Q?problem=3F?= Date: Fri, 29 Feb 2008 09:12:01 +0100 Message-ID: <872d9b69db95a1b08319e935595743cc@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: Maurice Hilarius Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Fri, 29 Feb 2008 00:53:06 -0700, Maurice Hilarius wrote: > Michael Guntsche wrote: >> .. >> While the result for XFS is different, reading is actually faster, the >> differnece between xfs and xfs on lvm is still there. >> >> > Great. At least now the figures are more realistic. >> pvcreate was called so that the first PE starts exactly at 256K, no sunits >> where used with mkfs.xfs for the lvm case. >> >> I still do not understand the read output at all. >> > That is certainly a puzzle. Is it possible that my computer is just too slow to get good read results? I wonder since writing seems to be nearly similar. I just tried with an ext3 FS. Version 1.03c ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP lvm-al8g-ext3 8G 45029 27 22436 29 55034 45 192.0 3 While reading is a little bit faster it's nowhere near the speed I get on md0 itself. Kind regards, Michael