From owner-freebsd-stable@FreeBSD.ORG Fri May 1 21:27:59 2009 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1F5351065679 for ; Fri, 1 May 2009 21:27:59 +0000 (UTC) (envelope-from mike@sentex.net) Received: from lava.sentex.ca (pyroxene.sentex.ca [199.212.134.18]) by mx1.freebsd.org (Postfix) with ESMTP id E0A078FC2A for ; Fri, 1 May 2009 21:27:58 +0000 (UTC) (envelope-from mike@sentex.net) Received: from mdt-xp.sentex.net (simeon.sentex.ca [192.168.43.27]) by lava.sentex.ca (8.14.3/8.14.3) with ESMTP id n41LQiIk045684; Fri, 1 May 2009 17:26:44 -0400 (EDT) (envelope-from mike@sentex.net) Message-Id: <200905012126.n41LQiIk045684@lava.sentex.ca> X-Mailer: QUALCOMM Windows Eudora Version 7.1.0.9 Date: Fri, 01 May 2009 17:27:49 -0400 To: Pete French , freebsd-stable@freebsd.org From: Mike Tancsa In-Reply-To: References: <200905012041.n41Kf47B045440@lava.sentex.ca> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Cc: Subject: Re: current zfs tuning in RELENG_7 (AMD64) suggestions ? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 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, 01 May 2009 21:27:59 -0000 At 04:53 PM 5/1/2009, Pete French wrote: >The tuning isn't there to improve performance, it's there to prevent >the box going titus due to a panic when the ARC gets too big, and >you are missing the mian one, which is to limit the size of the ARC. >On recent versions of BSD (and you are running 7.2, so thats fine) then >the defaults for kmem size are fine, but you still need something like this: > >vfs.zfs.arc_max="256M" > >In there to stop the ARC growing. thats the only tuning I have on >my 4 gig machine, which takes a steady stream of data and is used >for taking backup snapshots. ZFS is excellent, and for me is perfectly >stable, to the point where I am starting to roll it out to production >machines, with the above tuning. Thanks for the feedback. We too have had good results with zfs for what we have used it for. Our primary backup server has a traditional raid5 spool as well as a zfs spool and it has been working quite well in the last 6months. In that period we did swap out a dead drive, a dying drive and added a new drive to expand the pool. We are just expanding our DR site's backup server and will make use of ZFS there. Stability / reliability is our main goal for this app so I will take a look at the arc_max setting ---Mike