From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Theepan" Subject: Re: IDE Performance issues Date: Tue, 2 Sep 2003 15:48:40 +0200 Sender: linux-ide-owner@vger.kernel.org Message-ID: <01cf01c37158$ebd80750$0200a8c0@tornado> References: <002a01c37117$68abc560$0200a8c0@tornado> <200309021419.55006.bzolnier@elka.pw.edu.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Return-path: Received: from x1-6-00-a0-c9-de-85-f2.k78.webspeed.dk ([80.197.249.79]:48790 "EHLO storm.stormchasers.dk") by vger.kernel.org with ESMTP id S263430AbTIBNtG (ORCPT ); Tue, 2 Sep 2003 09:49:06 -0400 List-Id: linux-ide@vger.kernel.org To: Bartlomiej Zolnierkiewicz Cc: linux-ide@vger.kernel.org From: "Bartlomiej Zolnierkiewicz" To: "Theepan" Cc: Sent: Tuesday, September 02, 2003 2:19 PM Subject: Re: IDE Performance issues > > (I tried to send his mail to both linux-ide@ and linux-raid@ lists, but it > > only arrived at linux-raid@ - I guess one cannot specify multiple targets > > in the To: field, which is why I'm resending to this list only. I've also > > edited this email to exclude RAID details.) > > I think I've seen this mail on linux-ide@ previously. The reason I thought it never arrived was simply because I didn't get this e-mail back myself. It seems that I have been unsubscribed automatically some time ago. Anyway, I am subscribed again and I didn't want to send another mail to apologize the doubles, which would only create more traffic. Consider this e-mail the apology e-mail. :) > > zcav, a tool from bonnie++ package, was used to measure the sequential read > > rate. All disks were able to sustain minimum 30MB/s when accessed > > seperately. When accessed simultaneously I get these results: > > > > When accessing 1 disk, the read rate was 30MB/s (as expected). > > When accessing 2 disks, the read rate was 60MB/s (30MB/s on each disk, as > > expected) > > When accessing 3 disks, the read rate was 60MB/s (20MB/s on each disk, > > dropping 10Mb/s) > > When accessing 4 disks, the read rate was 60MB/s (15MB/s on each disk, > > dropping 15Mb/s) > > Have you tried with RAID0? > What makes you think its IDE issue, not a RAID one? It wouldn't do any good trying RAID0 if the underlying layer cannot deliver the data faster. The 4 above "benchmarks" are performed directly on the disks rather than on the RAID setup, which eliminates any overhead RAID may bring. -- Theepan