From owner-freebsd-fs@FreeBSD.ORG Sat Sep 4 01:09:44 2010 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8D9D210656D1 for ; Sat, 4 Sep 2010 01:09:44 +0000 (UTC) (envelope-from artemb@gmail.com) Received: from mail-ww0-f50.google.com (mail-ww0-f50.google.com [74.125.82.50]) by mx1.freebsd.org (Postfix) with ESMTP id 22E5C8FC13 for ; Sat, 4 Sep 2010 01:09:43 +0000 (UTC) Received: by wwb18 with SMTP id 18so44996wwb.31 for ; Fri, 03 Sep 2010 18:09:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:sender:received :in-reply-to:references:date:x-google-sender-auth:message-id:subject :from:to:cc:content-type; bh=/4uAYikoJAzJA2tUc9vqxGr5HdXmzidXtxSGchJ2Xew=; b=qXy1/59bVYurVJvSKVQ+Llzh90ZvWM9KqOcDCNQNS2zGz3xx2I0DxwCc5qqmoiNUb0 ABa9/KLhLk6Jl93McoktalGxyv/jlZF8RrVDJEbEwaqjsUe3BAtmhBJ8+SY082kXZyTV sQhF/7ik/sgpJbMgNisnA971d5yiOIR2FXhBI= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; b=JpQe/5haQrACOmxjSUHIQyEPCbGL8+g2gYTk+tfEzsaxns6W3r0s8it6TTp7e21huT o7ItzHWNq/k7ykoAQvomviEwOEpYJrZb76x8SvGdMx/wsR0Rb6onsb/PEkrPgxlKv+AI y9XvNt0gzWD9i2sANAeSHQXiFVjSTog6xtCow= MIME-Version: 1.0 Received: by 10.216.26.194 with SMTP id c44mr698714wea.104.1283562583096; Fri, 03 Sep 2010 18:09:43 -0700 (PDT) Sender: artemb@gmail.com Received: by 10.216.144.227 with HTTP; Fri, 3 Sep 2010 18:09:43 -0700 (PDT) In-Reply-To: <5DB6E7C798E44D33A05673F4B773405E@multiplay.co.uk> References: <5DB6E7C798E44D33A05673F4B773405E@multiplay.co.uk> Date: Fri, 3 Sep 2010 18:09:43 -0700 X-Google-Sender-Auth: L_gGwiA6gufCetvl-if7G5HRVy4 Message-ID: From: Artem Belevich To: Steven Hartland Content-Type: text/plain; charset=ISO-8859-1 Cc: freebsd-fs@freebsd.org Subject: Re: zfs very poor performance compared to ufs due to lack of cache? X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 04 Sep 2010 01:09:44 -0000 > For reference top shows:- > Mem: 42M Active, 3129M Inact, 565M Wired, 3188K Cache, 19M Buf, 203M Free Here's your problem -- inactive list got all your memory and starved ZFS ARC. Easy workaround is to set vfs.zfs.arc_min to a value that would guarantee that ARC does not give up too much memory. Let's say - 2GB. Be warned that it would effectively make those 2GB unavailable to applications. Long term, though, there were number of patches posted on freebsd-current and freebsd-hackers recently that do improve that particular issue with ZFS. This patch in particular may help you: http://lists.freebsd.org/pipermail/freebsd-hackers/2010-August/032731.html > Swap: 4096M Total, 1180K Used, 4095M Free > > So what are we missing and how to we get zfs to perform like ufs > and use all free ram as cache? --Artem