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 DA86F1381F3 for ; Thu, 20 Jun 2013 19:16:26 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id BA3EBE09E2; Thu, 20 Jun 2013 19:16:24 +0000 (UTC) Received: from mail-bk0-f52.google.com (mail-bk0-f52.google.com [209.85.214.52]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id D1BA0E098A for ; Thu, 20 Jun 2013 19:16:23 +0000 (UTC) Received: by mail-bk0-f52.google.com with SMTP id d7so3068669bkh.25 for ; Thu, 20 Jun 2013 12:16:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; bh=RubjsIyotR30kN1dfgUXStg44dEy1JE3j2C9kYMznr0=; b=Tesv9SYuYx0ubl3tQsYyX4ltL3au9WWSdtWKhDkDXKujMnIJv1UeS2ZmAlEoy7oiKL aZk214NeeA2N8PxGvAHW8yLTxsKv4x3vSBglBFrjAikMrthBwbaTf0fW2x0+vSLjUUq5 PoSmL5HDLzcQl01BE2CTZ3/wg9eRp9zPXFTIDzHYBBpbNu6CmfSw+JbGptsXQXxMIPcI bBFqb1jJMeLwB3fhHNyqRTLyvGCAa2L3SL3ulFrJGf6rXr6L1QN6nIh8gPluJhdk4alf 8i1+RJTbgB7DDqCc11slwwGsbb4rfhBnyaykVlnOBQ62XV0sHb+9XkPDQZw3Jmn2tCU2 CeuA== X-Received: by 10.204.237.136 with SMTP id ko8mr1286185bkb.154.1371755781833; Thu, 20 Jun 2013 12:16:21 -0700 (PDT) Received: from [192.168.178.21] (p549C723D.dip0.t-ipconnect.de. [84.156.114.61]) by mx.google.com with ESMTPSA id ch16sm723900bkb.17.2013.06.20.12.16.20 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 20 Jun 2013 12:16:20 -0700 (PDT) Message-ID: <51C35503.2020608@googlemail.com> Date: Thu, 20 Jun 2013 21:16:19 +0200 From: Volker Armin Hemmann User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130615 Thunderbird/17.0.6 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 To: gentoo-amd64@lists.gentoo.org Subject: Re: [gentoo-amd64] Is my RAID performance bad possibly due to starting sector value? References: In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Archives-Salt: 19638e82-5457-43cd-a527-95ae5cd9b40c X-Archives-Hash: 5f955b23af2d7ee665c630f356c78b8d Am 20.06.2013 21:10, schrieb Mark Knecht: > Hi, > Does anyone know of info on how the starting sector number might > impact RAID performance under Gentoo? The drives are WD-500G RE3 > drives shown here: > > http://www.amazon.com/Western-Digital-WD5002ABYS-3-5-inch-Enterprise/dp/B001EMZPD0/ref=cm_cr_pr_product_top > > These are NOT 4k sector sized drives. > > Specifically I'm a 5-drive RAID6 for about 1.45TB of storage. My > benchmarking seems abysmal at around 40MB/S using dd copying large > files. It's higher, around 80MB/S if the file being transferred is > coming from an SSD, but even 80MB/S seems slow to me. I see a LOT of > wait time in top. And my 'large file' copies might not be large enough > as the machine has 24GB of DRAM and I've only been copying 21GB so > it's possible some of that is cached. > > Then I looked again at how I partitioned the drives originally and > see the starting sector of sector 3 as 8594775. I started wondering if > something like 4K block sizes at the file system level might be > getting munged across 16k chunk sizes in the RAID. Maybe the blocks > are being torn apart in bad ways for performance? That led me down a > bunch of rabbit holes and I haven't found any light yet. > > Looking for some thoughtful ideas from those more experienced in this area. > > Cheers, > Mark > > man mkfs.xfs man mkfs.ext4 look for stripe size etc. Have fun.