From owner-freebsd-fs@freebsd.org Tue May 17 21:28:24 2016 Return-Path: Delivered-To: freebsd-fs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id EA9A2B3F906 for ; Tue, 17 May 2016 21:28:24 +0000 (UTC) (envelope-from steven@multiplay.co.uk) Received: from mail-wm0-x232.google.com (mail-wm0-x232.google.com [IPv6:2a00:1450:400c:c09::232]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id A664C1A2B for ; Tue, 17 May 2016 21:28:24 +0000 (UTC) (envelope-from steven@multiplay.co.uk) Received: by mail-wm0-x232.google.com with SMTP id r12so7433440wme.0 for ; Tue, 17 May 2016 14:28:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=multiplay-co-uk.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc; bh=z7vstwTQiUNHIdnrUIAx7ViqJDOqm6/6JMO4H7a+tYQ=; b=AAdvZCT1eg2AgFpWM6/1yLfVKmwRGPAIyLDV5vppFlDbpsypakG/Qc5YyjGBOfAm2O 4+bjR82+v77Q7ixDolp0+cL6ho0HEsZS6/BKnbSGDUmBsqIPw4YntSWJy9trTAdEzKlc lsbef3u6bpNcD8IEQ4Q1SOKv/kGvLH4Y5cb4bYHO4TVHovSrKHoNhn8/5yXgU1XE5A56 BZU4hMmn7EpiUMmd4vOivHHk4p71mWdiGalhpHHt4LBnVnA/rUmIsNmKLc5O8pD1Jg3C /2oY1o2CH2p/55NNLr2QsAFqtERLuGYWHPeRbAd7FKYqgMcd74aMSDiV1bliFTfN+TIZ P5fA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc; bh=z7vstwTQiUNHIdnrUIAx7ViqJDOqm6/6JMO4H7a+tYQ=; b=ipZR72+TlMbikBQ1tGMYBJayjW+HUGrMYaxP8QUxh3jW3T++2IlmNhEc5VM5jS8/Zo wuRpxGaTUx+n43O49oSs2oSa3gVPKcACRm72vfL2+LhYQ3eDrN9efFu2z3VU2Xen+olo /aabXnJPjJfK1VNTURQ7MF3VDL/a4/yxfsy8Xlgn7+C+vmb5e5PCN0hYT928KUML6h8L uksf9UhlytvdgYcL7DuOQILmUrFknfa3dvSOiCP16iW9vn69+pD4zt5Vu3oMlWsIEztJ A0iRrZd+xOda60CrPOjUTiD6H9Q4h3uev+IxpGfbXrjZweWmICfFdNOEuuJgzGANi4rF xsvg== X-Gm-Message-State: AOPr4FUKSlKvD0j2neQYKuun6V3pti+KkHKGGHvuZ9B41tvnO9MuNwfxnSL6RuMZ3OnulrUDY/+kfEEnDoauHU4i MIME-Version: 1.0 X-Received: by 10.194.163.229 with SMTP id yl5mr3582806wjb.6.1463520503074; Tue, 17 May 2016 14:28:23 -0700 (PDT) Received: by 10.28.93.203 with HTTP; Tue, 17 May 2016 14:28:22 -0700 (PDT) In-Reply-To: References: <8441f4c0-f8d1-f540-b928-7ae60998ba8e@lexa.ru> <16e474da-6b20-2e51-9981-3c262eaff350@lexa.ru> <1e012e43-a49b-6923-3f0a-ee77a5c8fa70@lexa.ru> <86shxgsdzh.fsf@WorkBox.Home> Date: Tue, 17 May 2016 22:28:22 +0100 Message-ID: Subject: Re: ZFS performance bottlenecks: CPU or RAM or anything else? From: Steven Hartland To: Freddie Cash Cc: "Brandon J. Wandersee" , "freebsd-fs@freebsd.org" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.22 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 May 2016 21:28:25 -0000 Tbh if the results were from more than 6 months ago they are likely quite out of date as things have changed quite significantly in that period, so retesting would be advised. On Tuesday, 17 May 2016, Freddie Cash wrote: > On Tue, May 17, 2016 at 2:11 PM, Steven Hartland > wrote: > >> Raidz is limited essential limited to a single drive performance >> per dev for read and write while mirror is single drive performance for >> write its number of drives for read. Don't forget mirror is not limited = to >> two it can be three, four or more; so if you need more read throughput y= ou >> can add drives to the mirror. >> >> To increase raidz performance you need to add more vdevs. While this >> doesn't have to be double i.e. the same vdev config as the first it >> generally a good idea. >> >> Don't forget that while it rebalances write performance of a multi vdev >> raidz will be limited to the added vdev. >> > > =E2=80=8BEverybody is missing the point of the OP. > > They're not asking for ways to improve the performance of a raidz-based > pool; they're asking why they get different performance metrics from the > exact same pool when they change the CPU and RAM. > > And, more importantly, why a Core-i3-based system shows better performanc= e > than a Core-i7-based system.=E2=80=8B Is there something inherent to the= way ZFS > works that favours one setup over another (lower CPU core counts running = at > higher speeds is better/worse than higher CPU core counts running at lowe= r > speeds; more RAM channels is better/worse; things like that). > > > -- > Freddie Cash > fjwcash@gmail.com >