From owner-freebsd-stable@FreeBSD.ORG Fri May 10 01:47:30 2013 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 6B1EFB64 for ; Fri, 10 May 2013 01:47:30 +0000 (UTC) (envelope-from benjamindadams@gmail.com) Received: from mail-ob0-x234.google.com (mail-ob0-x234.google.com [IPv6:2607:f8b0:4003:c01::234]) by mx1.freebsd.org (Postfix) with ESMTP id EC093FB8 for ; Fri, 10 May 2013 01:47:29 +0000 (UTC) Received: by mail-ob0-f180.google.com with SMTP id xk17so1492550obc.39 for ; Thu, 09 May 2013 18:47:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:message-id:date:from:user-agent:mime-version:to:cc :subject:references:in-reply-to:content-type :content-transfer-encoding; bh=OKuANdhMRqaio12VN9X9OJ0/QNUCsB599akR6vpMmf8=; b=WoOOPUntn+4mgfrXAe1Pw4oiStFbBc54nWD48F/QeRYUQrWOWMF1o+GMtEaZG9zfXB LJdPCqhmPPwr9rIkc+zIp/d838XYbwFzh/u+V4HMDsTy4GmC4v7qD3AQ1fFpqZ3+eatb KDrardy4h4IUmKxLjEFiz2SvzKkqavTWreaa6Nf20mLYs7dMHCnWg2BjznpccKzOQ8CK 2LcriD/qWd0lAk/ZqC3viydaGk4DPgGpUD1Cuyj8yHXxPdl8AJKY8g9Q86QXu/xvOVee EHH8BAc8uRisGHPfHNCFhvwVUK7rpe3BhP2bOeim231EefBRTWq1dfKolgZqc/LVeL8s oMNg== X-Received: by 10.60.141.164 with SMTP id rp4mr5993010oeb.38.1368150449514; Thu, 09 May 2013 18:47:29 -0700 (PDT) Received: from localhost.localdomain (cpe-67-249-53-57.twcny.res.rr.com. [67.249.53.57]) by mx.google.com with ESMTPSA id ri8sm875900oeb.0.2013.05.09.18.47.28 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Thu, 09 May 2013 18:47:28 -0700 (PDT) Message-ID: <518C51AF.5050609@gmail.com> Date: Thu, 09 May 2013 21:47:27 -0400 From: Benjamin Adams User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130402 Thunderbird/17.0.5 MIME-Version: 1.0 To: Shane Ambler Subject: Re: recommended memory for zfs References: <518BA237.3030700@gmail.com> <518C450B.5070809@ShaneWare.Biz> In-Reply-To: <518C450B.5070809@ShaneWare.Biz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-stable@freebsd.org X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 10 May 2013 01:47:30 -0000 On 05/09/2013 08:53 PM, Shane Ambler wrote: > On 09/05/2013 22:48, Benjamin Adams wrote: >> Hello zfs question about memory. >> I heard zfs is very ram hungry. >> Service looking to run: >> - nginx >> - postgres >> - php-fpm >> - python >> >> I have a machine with two quad core cpus but only 4 G Memory >> >> I'm looking to buy more ram now. >> What would be the recommend amount of memory for zfs across 6 drives on >> this setup? >> > > I believe I heard a calculation of 1GB cache per 1TB of disk. But > basically zfs will use all free ram available if you access that much > data from disk. You will want to set vfs.zfs.arc_max to allow enough > ram for your apps to work in. > > If you consider the files for your website and the data you store you > may find that you would never fill more than 500MB of cache. > > If you will be serving large media files that will easily use up the > cache you could give them their own filesystem that only caches > metadata - zfs set primarycache=metadata zroot/mediafiles > > Thanks for all the replies Size of DB and HD's are: Current DB Size = 23 GB HD sizes = (6) 500 GB drives