From owner-freebsd-stable@FreeBSD.ORG Mon Feb 15 18:03:41 2010 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 0CE94106568D for ; Mon, 15 Feb 2010 18:03:41 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from mail-iw0-f175.google.com (mail-iw0-f175.google.com [209.85.223.175]) by mx1.freebsd.org (Postfix) with ESMTP id C8D3F8FC26 for ; Mon, 15 Feb 2010 18:03:40 +0000 (UTC) Received: by iwn5 with SMTP id 5so1997598iwn.9 for ; Mon, 15 Feb 2010 10:03:40 -0800 (PST) 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:content-type; bh=NjadGosjeWzMzvByncnbZBevOTP8F22ZaZNjpwRiObE=; b=al8GbBvM1hX6uLAFvVdPyPRnkTf1ZcyJGAlXg5glhb1eVQguTT5VOBMCNVYo7aWBSF 9wm7KaRdxjtDUi6T5AlF2iwmdbpjf2QuAmhr70M2481YH1VOC6RstPjXGD/3ALtMCBCA 18rbfW786tfTxigOr27b+XMuftxFlkMYUyn6Q= 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 :content-type; b=p+PARGMetKfdFc96OjdO3R0hoJHXji4HNvG+1PEsDU6sEVMXQDv2ii9L8bEyhIJIlf 9ZKRRQ6JWPUcwlvUQxWOjiL6lrt5q+EdmVYLhFHiVshdQ7Sb6v/tyQOhohxAyWUg34xQ nqZ5GVsBBl6b9rsZULrjdgis50xZQij5Oqr1E= MIME-Version: 1.0 Received: by 10.231.159.207 with SMTP id k15mr4402832ibx.52.1266257020207; Mon, 15 Feb 2010 10:03:40 -0800 (PST) In-Reply-To: <4B7989AE.1050203@witchspace.com> References: <4B7989AE.1050203@witchspace.com> Date: Mon, 15 Feb 2010 10:03:40 -0800 Message-ID: From: Freddie Cash To: freebsd-stable@freebsd.org Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Subject: Re: More zfs benchmarks 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: Mon, 15 Feb 2010 18:03:41 -0000 On Mon, Feb 15, 2010 at 9:51 AM, Jonathan Belson wrote: > On 14/02/2010 17:28, Jonathan Belson wrote: > >> After reading some earlier threads about zfs performance, I decided to >> test my own server. I found the results rather surprising... >> > > Thanks to everyone who responded. I experimented with my load.conf > settings, leaving me with the following: > > vm.kmem_size="1280M" > vfs.zfs.prefetch_disable="1" > > That kmem_size seems quite big for a machine with only (!) 2GB of RAM, but > I wanted to see if it gave better results than 1024MB (it did, an extra > ~5MB/s). > For a system with 2 GB of RAM, and possibly slow harddrives, consider adding a "cache" vdev (L2ARC). The 4 GB and larger USB flash drives are getting to be pretty fast for reads (which is what the L2ARC is for). On my home system, which is a 32-bit FreeBSD 8-STABLE box with a 3.0 GHz P4 and 2 GB of RAM, adding a 4 GB Transcend JetFlash has done wonders for improving stability and read speed. Most of my apps now load from the USB stick instead of the slow raidz1 vdev (3x 120 GB SATA drives). Haven't done any real benchmarks yet (still upgrading to KDE 4.4), but things feel smoother, and it hasn't locked up since adding the USB stick. On this box, running ktorrent 24/7 used to lock up the box after 3-5 days (can't even toggle numlock). This box uses a kmem_max of 1 GB, and an arc_max of 512 MB. With a 4 GB L2ARC. :) -- Freddie Cash fjwcash@gmail.com