From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262153AbUBNQZ5 (ORCPT ); Sat, 14 Feb 2004 11:25:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262228AbUBNQZ5 (ORCPT ); Sat, 14 Feb 2004 11:25:57 -0500 Received: from pop.gmx.de ([213.165.64.20]:37837 "HELO mail.gmx.net") by vger.kernel.org with SMTP id S262153AbUBNQZy (ORCPT ); Sat, 14 Feb 2004 11:25:54 -0500 Date: Sat, 14 Feb 2004 17:25:52 +0100 (MET) From: "Daniel Blueman" To: Timothy Miller Cc: aradford@3WARE.com, linux-kernel@vger.kernel.org MIME-Version: 1.0 References: <402D6354.3010801@techsource.com> Subject: Re: File system performance, hardware performance, ext3, 3ware RA ID1, etc. X-Priority: 3 (Normal) X-Authenticated: #8973862 Message-ID: <30156.1076775952@www12.gmx.net> X-Mailer: WWW-Mail 1.6 (Global Message Exchange) X-Flags: 0001 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Tim, Do you get the same numbers (but slightly higher, as this is will measure from a smaller portion of outer zones) with: # hdparm -t /dev/sda ? > Adam Radford wrote: > > Perhaps you are issuing non purely sequential IO. The card firmware > does > > some > > reodering, but at some point it will cause performance degradation. Can > you > > try > > kernel 2.6 w/xfs? > > Not any time soon, but as I mentioned earlier, I measured 13.9 megs/sec > when I ran this command: > > time dd if=/dev/zero of=/dev/sda2 bs=1024k count=1024 > > No file system was involved; I was simply writing zeros to the block > device (swap partition with swap off). It took 73.522 seconds to do the > above operation. Also, I was running in single-user mode while doing > the test. > > > > > Also, in my experience, the 'raw io' interface doesn't issue any > > asynchronous IO. The > > card _definately_ needs asynchronous IO posted to it or you will not get > > good results > > because you won't get all the drives busy. > > With RAID1, both drives will be written with the same data. There is no > need to be asynchronous, since it's all completely linear and sequential > with large data blocks. -- Daniel J Blueman GMX ProMail (250 MB Mailbox, 50 FreeSMS, Virenschutz, 2,99 EUR/Monat...) jetzt 3 Monate GRATIS + 3x DER SPIEGEL +++ http://www.gmx.net/derspiegel +++