From owner-freebsd-questions@FreeBSD.ORG Sat Mar 20 02:32:51 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id BB0F0106566B; Sat, 20 Mar 2010 02:32:51 +0000 (UTC) (envelope-from amvandemore@gmail.com) Received: from mail-pv0-f182.google.com (mail-pv0-f182.google.com [74.125.83.182]) by mx1.freebsd.org (Postfix) with ESMTP id 762778FC0A; Sat, 20 Mar 2010 02:32:51 +0000 (UTC) Received: by pvc7 with SMTP id 7so646974pvc.13 for ; Fri, 19 Mar 2010 19:32:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type; bh=mPNlbUL+WVv1mC9T/ih8I16WRWUWrHlDRJWYTNG8TgQ=; b=Nb8gj7NroCQVlnt0obX5bTbXHiO5a5f/fDovdjyj5PTLdgfTlcB5ecHEfHGPY2P+dt qh4edUhg9NFfFXv2ze9+HQm5eOPLdmQSxLLfhDn/G9/wPDP+VZyUOXiK1hiyPDOv67k9 GLKtrD/9OD4WGPwye5mhJ+s70g52jaRjKsotM= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=IID94jeo8fUzY/Vunz/G8Ypfh25dRkn+q5LhrzZLW/1v6jyzQdXXC0UhoISLVU65YO waR7opeOmmBZiTGLo3oTVXlyX1IMLJAwfm/F5CcgBnjeDs7yzvvA7zvRQ/LwcgcIppW0 4DE8Jgac68MfT4nsT6Xh653YEzNLQgjRmiSC4= MIME-Version: 1.0 Received: by 10.142.8.22 with SMTP id 22mr1435039wfh.194.1269052370909; Fri, 19 Mar 2010 19:32:50 -0700 (PDT) In-Reply-To: References: Date: Fri, 19 Mar 2010 21:32:50 -0500 Message-ID: <6201873e1003191932g447cb261rbc928324408b959b@mail.gmail.com> From: Adam Vande More To: Dan Naumov Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-net@freebsd.org, freebsd-performance@freebsd.org, FreeBSD-STABLE Mailing List , freebsd-questions@freebsd.org Subject: Re: Samba read speed performance tuning X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 20 Mar 2010 02:32:51 -0000 On Fri, Mar 19, 2010 at 8:28 PM, Dan Naumov wrote: > Oh my god... Why did noone tell me how much of an enormous performance > boost vfs.zfs.prefetch_disable=0 (aka actually enabling prefetch) is. > My local reads off the mirror pool jumped from 75mb/s to 96mb/s (ie. > they are now nearly 25% faster than reading off an individual disk) > and reads off a Samba share skyrocketed from 50mb/s to 90mb/s. > > By default, FreeBSD sets vfs.zfs.prefetch_disable to 1 on any i386 > systems and on any amd64 systems with less than 4GB of avaiable > memory. My system is amd64 with 4gb ram, but integrated video eats > some of that, so the autotuning disabled the prefetch. I had read up > on it and a fair amount of people seemed to have performance issues > caused by having prefetch enabled and get better results with it > turned off, in my case however, it seems that enabling it gave a > really solid boost to performance. > My home VBox server is similar specs and I enabled the prefetch from the start. A few days ago, I added an intel SSD as the zpool cache device and the read speed is mind blowing now. This is from inside a VM frunning on it meaning ad0 is really a vdi. Once the cache is populated, HD latency is mostly a thing of the past. # diskinfo -tv /dev/ad0 /dev/ad0 512 # sectorsize 12884901888 # mediasize in bytes (12G) 25165824 # mediasize in sectors 24966 # Cylinders according to firmware. 16 # Heads according to firmware. 63 # Sectors according to firmware. VBf9752473-05343e4e # Disk ident. Seek times: Full stroke: 250 iter in 0.082321 sec = 0.329 msec Half stroke: 250 iter in 0.078944 sec = 0.316 msec Quarter stroke: 500 iter in 0.161266 sec = 0.323 msec Short forward: 400 iter in 0.128624 sec = 0.322 msec Short backward: 400 iter in 0.131770 sec = 0.329 msec Seq outer: 2048 iter in 0.667510 sec = 0.326 msec Seq inner: 2048 iter in 0.691691 sec = 0.338 msec Transfer rates: outside: 102400 kbytes in 0.722864 sec = 141659 kbytes/sec middle: 102400 kbytes in 0.813619 sec = 125857 kbytes/sec inside: 102400 kbytes in 0.838129 sec = 122177 kbytes/sec -- Adam Vande More