From mboxrd@z Thu Jan 1 00:00:00 1970 From: Erik Slagter Subject: Readahead with softraid1 Date: Fri, 08 Jul 2005 14:00:29 +0200 Message-ID: <1120824029.23681.18.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-MZBx49+zyIMpr65yCxJD" Return-path: Received: from oldconomy.demon.nl ([212.238.217.56]:61611 "EHLO artemis.slagter.name") by vger.kernel.org with ESMTP id S262459AbVGHMBG (ORCPT ); Fri, 8 Jul 2005 08:01:06 -0400 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-ide@vger.kernel.org --=-MZBx49+zyIMpr65yCxJD Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hi, I am using softraid 1 on two sata disks and I'm trying to get the best possible performance. IMHO read actions (if properly addressed) should be split over the two drivers and performed independently. However, I don't notice anything to back this up. The read performance (with the dreaded hdparm) shows read performance on sda,sdb and md0 exactly the same. I've been playing a bit with readahead and it does matter a bit in that if I disable readahead for sda/sdb completely, the read rate for these goes completely down (to be expected) whilst the read rate on md0 stays the same (also a bit to be expected). Other combinations do not show any significant impact. I also played with the i/o scheduler and nr_requests (as from previous messages here). What am I doing wrong here??? --=-MZBx49+zyIMpr65yCxJD Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQBCzmrdJgD/6j32wUYRAgriAJ4iA9Su/Z2nI93q5fSzQTiHNXPm4ACdHfsO ytFL2nau2ImWTvxKRxQFO68= =53r0 -----END PGP SIGNATURE----- --=-MZBx49+zyIMpr65yCxJD--