From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265596AbUEZNMk (ORCPT ); Wed, 26 May 2004 09:12:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265678AbUEZNIe (ORCPT ); Wed, 26 May 2004 09:08:34 -0400 Received: from ts46-01-qdr3367.knnwck.wa.charter.com ([68.118.221.54]:60301 "EHLO bob.felix.fam") by vger.kernel.org with ESMTP id S265679AbUEZNHH (ORCPT ); Wed, 26 May 2004 09:07:07 -0400 Date: Wed, 26 May 2004 06:06:44 -0700 From: evan-lkml@felix.homeip.net To: Andrey Nekrasov Cc: linux-kernel@vger.kernel.org Subject: Re: sata promise and software raid5... Message-ID: <20040526130644.GA15042@felix.homeip.net> Reply-To: evan-lkml@felix.homeip.net References: <1236867749.20040526034657@spylog.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1236867749.20040526034657@spylog.ru> User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org You need to test all the disks running at once, this should give a much clearer picture of how the system will perform with a raid volume. a simple test is like so: -> hdparm -t /dev/sda2 & hdparm -t /dev/sdc2 & hdparm -t /dev/sdc2 & hdparm -t /dev/sdd2 This will get them all going at once, but may jumble the output a bit. Evan On Wed, May 26, 2004 at 03:46:57AM +0400, Andrey Nekrasov wrote: > Hello, > > controller - Promise SATA 150 TX4, linux 2.6.7-rc1-bk1, HDD Maxtor > 250Gb (x4) > > Why so slowly reads (and writes) with software raid5? > > gnome:~ # hdparm -t /dev/sda2 > > /dev/sda2: > Timing buffered disk reads: 148 MB in 3.01 seconds = 49.16 MB/sec > gnome:~ # hdparm -t /dev/sdb2 > > /dev/sdb2: > Timing buffered disk reads: 148 MB in 3.02 seconds = 49.01 MB/sec > gnome:~ # hdparm -t /dev/sdc2 > > /dev/sdc2: > Timing buffered disk reads: 148 MB in 3.03 seconds = 48.90 MB/sec > gnome:~ # hdparm -t /dev/sdd2 > > /dev/sdd2: > Timing buffered disk reads: 144 MB in 3.00 seconds = 47.96 MB/sec > gnome:~ # > gnome:~ # > gnome:~ # hdparm -t /dev/md0 > > /dev/md0: > Timing buffered disk reads: 64 MB in 3.12 seconds = 20.52 MB/sec > gnome:~ # > > > gnome:~ # cat /etc/raidtab > raiddev /dev/md0 > raid-level 5 > nr-raid-disks 4 > nr-spare-disks 0 > persistent-superblock 1 > parity-algorithm left-symmetric > chunk-size 1024 > > device /dev/sda2 > raid-disk 0 > > device /dev/sdb2 > raid-disk 1 > > device /dev/sdc2 > raid-disk 2 > > device /dev/sdd2 > raid-disk 3 > > > bye > -- > > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/