From owner-freebsd-current@FreeBSD.ORG Fri Apr 17 19:05:58 2009 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 31283106566B; Fri, 17 Apr 2009 19:05:58 +0000 (UTC) (envelope-from ticso@cicely7.cicely.de) Received: from raven.bwct.de (raven.bwct.de [85.159.14.73]) by mx1.freebsd.org (Postfix) with ESMTP id 95F608FC16; Fri, 17 Apr 2009 19:05:57 +0000 (UTC) (envelope-from ticso@cicely7.cicely.de) Received: from cicely5.cicely.de ([10.1.1.7]) by raven.bwct.de (8.13.4/8.13.4) with ESMTP id n3HJ5tmF063212 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 17 Apr 2009 21:05:56 +0200 (CEST) (envelope-from ticso@cicely7.cicely.de) Received: from cicely7.cicely.de (cicely7.cicely.de [10.1.1.9]) by cicely5.cicely.de (8.14.2/8.14.2) with ESMTP id n3HJ5q2p027708 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 17 Apr 2009 21:05:52 +0200 (CEST) (envelope-from ticso@cicely7.cicely.de) Received: from cicely7.cicely.de (localhost [127.0.0.1]) by cicely7.cicely.de (8.14.2/8.14.2) with ESMTP id n3HJ5qJX016460; Fri, 17 Apr 2009 21:05:52 +0200 (CEST) (envelope-from ticso@cicely7.cicely.de) Received: (from ticso@localhost) by cicely7.cicely.de (8.14.2/8.14.2/Submit) id n3HJ5qeY016459; Fri, 17 Apr 2009 21:05:52 +0200 (CEST) (envelope-from ticso) Date: Fri, 17 Apr 2009 21:05:52 +0200 From: Bernd Walter To: Marius =?iso-8859-1?Q?N=FCnnerich?= Message-ID: <20090417190551.GT11551@cicely7.cicely.de> References: <20090417145024.205173ighmwi4j0o@webmail.leidinger.net> <20090417141817.GR11551@cicely7.cicely.de> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Operating-System: FreeBSD cicely7.cicely.de 7.0-STABLE i386 User-Agent: Mutt/1.5.11 X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED=-1.8, AWL=0.000, BAYES_00=-2.599 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on spamd.cicely.de Cc: Alexander Leidinger , ticso@cicely.de, fs@freebsd.org, current@freebsd.org Subject: Re: ZFS: unlimited arc cache growth? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: ticso@cicely.de List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 17 Apr 2009 19:05:58 -0000 On Fri, Apr 17, 2009 at 06:28:29PM +0200, Marius Nünnerich wrote: > On Fri, Apr 17, 2009 at 16:18, Bernd Walter wrote: > > On Fri, Apr 17, 2009 at 02:50:24PM +0200, Alexander Leidinger wrote: > >> Hi, > >> > >> to fs@, please CC me, as I'm not subscribed. > >> > >> I monitored (by hand) a while the sysctls kstat.zfs.misc.arcstats.size > >> and kstat.zfs.misc.arcstats.hdr_size. Both grow way higher (at some > >> point I've seen more than 500M) than what I have configured in > >> vfs.zfs.arc_max (40M). > > > > My understanding about this is the following: > > vfs.zfs.arc_min/max are not used as min max values. > > They are used as high/low watermarks. > > If arc is more than max the arc a thread is triggered to reduce the > > arc cache until min, but in the meantime other threads can still grow > > arc so there is a race between them. > > Hmm, if this is true the ARC size should go down to arc_min once it > did grow past arc_max and no new data is coming along but I do not > observe such a thing here. It simply stays near but below arc_max here > all the time. I have only /home on ZFS with moderate load. I had a few ideas why this could be, but scanning complete sys showed no point at all where arc_min is used. There are formular to set this value, but that's all I find. -- B.Walter http://www.bwct.de Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.