From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id C2CC91381F3 for ; Sat, 22 Jun 2013 22:15:38 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id C4D46E09F4; Sat, 22 Jun 2013 22:15:30 +0000 (UTC) Received: from catbert.rellim.com (catbert.rellim.com [204.17.205.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id EF33CE09F2 for ; Sat, 22 Jun 2013 22:15:29 +0000 (UTC) Received: from localhost ([IPv6:2001:470:e815:0:230:48ff:fe34:5fe2]) (authenticated bits=0) by catbert.rellim.com (8.14.5/8.14.5) with ESMTP id r5MMFPb7007053 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Sat, 22 Jun 2013 15:15:26 -0700 X-DKIM: OpenDKIM Filter v2.6.7 catbert.rellim.com r5MMFPb7007053 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=rellim.com; s=catbert; t=1371939326; bh=vBqjfZpgT959kC6CrDyvJhsUg7w0Nwhy0mdgvVY5S/0=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=qDOqpX85ogXSbtt5oF6TJ+SQbApkR3M2FUufR5JQn8Y+df2j3jGrPGEbvE8PO477o YSfUWnv8Czi+59eYaGl1g== Date: Sat, 22 Jun 2013 15:15:16 -0700 From: "Gary E. Miller" To: gentoo-amd64@lists.gentoo.org Cc: 1i5t5.duncan@cox.net Subject: Re: [gentoo-amd64] Re: Is my RAID performance bad possibly due to starting sector value? Message-ID: <20130622151516.7d0be796.gem@rellim.com> In-Reply-To: References: <20130621115043.32b99d94.gem@rellim.com> Organization: Rellim X-Mailer: Claws Mail 3.9.0 (GTK+ 2.24.17; x86_64-pc-linux-gnu) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-amd64@lists.gentoo.org Reply-to: gentoo-amd64@lists.gentoo.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/3QbgXpuwcpRe1AGhpLHUH/c"; protocol="application/pgp-signature" X-Archives-Salt: d48e0eb5-67de-4d65-b5d9-747c949bc829 X-Archives-Hash: 946291cb2ec36e9b1d4631ce62474974 --Sig_/3QbgXpuwcpRe1AGhpLHUH/c Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Yo Duncan! On Sat, 22 Jun 2013 14:34:36 +0000 (UTC) Duncan <1i5t5.duncan@cox.net> wrote: > >> On the read side I'm not sure if I'm understanding your point. I > >> agree that a so-designed RAID1 system could/might read smaller > >> portions of a larger read from RAID1 drives in parallel, taking > >> some data from one drive and some from another drive, and then > >> only take action corrective if one of the drives had troubles. > >> However I don't know that mdadm-based RAID1 does anything like > >> that. Does it? > >=20 > > It surely does. I have confirmed that at least monthly since md has > > existed in the kernel. >=20 > Out of curiosity, /how/ do you confirm that? I agree based on real > usage experience, but with a claim that you're confirming it at least > monthly, it sounds like you have a standardized/scripted test, and > I'm interested in what/how you do it. I have around 30 RAID1 sets in production right now. Some of them doing mostly reads and some mostly writes. Some are HDD and some SSD. The RAID sets are pushed pretty hard 24x7 and we watch the performance pretty closely to plan updates. I have collectd performance graphs going way back. RGDS GARY --------------------------------------------------------------------------- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97701 gem@rellim.com Tel:+1(541)382-8588 --Sig_/3QbgXpuwcpRe1AGhpLHUH/c Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (GNU/Linux) iEYEARECAAYFAlHGIfgACgkQBmnRqz71OvNKNACeKRwH21ZVQexK+gyS8Thhv+g/ 1tIAoI0r7+G6xG+PxelviQK/yj0epen1 =KLix -----END PGP SIGNATURE----- --Sig_/3QbgXpuwcpRe1AGhpLHUH/c--