From owner-freebsd-stable@FreeBSD.ORG Wed Jan 27 05:46:13 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 017341065670 for ; Wed, 27 Jan 2010 05:46:13 +0000 (UTC) (envelope-from gerrit@pmp.uni-hannover.de) Received: from mrelay1.uni-hannover.de (mrelay1.uni-hannover.de [130.75.2.106]) by mx1.freebsd.org (Postfix) with ESMTP id 660E08FC20 for ; Wed, 27 Jan 2010 05:46:12 +0000 (UTC) Received: from www.pmp.uni-hannover.de (www.pmp.uni-hannover.de [130.75.117.2]) by mrelay1.uni-hannover.de (8.14.2/8.14.2) with ESMTP id o0R5k6oO016777; Wed, 27 Jan 2010 06:46:08 +0100 Received: from pmp.uni-hannover.de (theq.pmp.uni-hannover.de [130.75.117.4]) by www.pmp.uni-hannover.de (Postfix) with SMTP id BE79224; Wed, 27 Jan 2010 06:46:06 +0100 (CET) Date: Wed, 27 Jan 2010 06:46:06 +0100 From: Gerrit =?ISO-8859-1?Q?K=FChn?= To: Damian Gerow Message-Id: <20100127064606.9c546283.gerrit@pmp.uni-hannover.de> In-Reply-To: <20100127001201.GE9206@plebeian.afflictions.org> References: <20100126235458.GA12634@swelter.hanley.stade.co.uk> <20100127001201.GE9206@plebeian.afflictions.org> Organization: Albert-Einstein-Institut (MPI =?ISO-8859-1?Q?f=FCr?= Gravitationsphysik & IGP =?ISO-8859-1?Q?Universit=E4t?= Hannover) X-Mailer: Sylpheed 2.4.2 (GTK+ 2.10.12; i386-portbld-freebsd6.1) Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-PMX-Version: 5.5.9.388399, Antispam-Engine: 2.7.2.376379, Antispam-Data: 2010.1.27.53621 Cc: freebsd-stable@freebsd.org Subject: Re: immense delayed write to file system (ZFS and UFS2), performance issues 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: Wed, 27 Jan 2010 05:46:13 -0000 On Tue, 26 Jan 2010 19:12:01 -0500 Damian Gerow wrote about Re: immense delayed write to file system (ZFS and UFS2), performance issues: DG> Adrian Wontroba wrote: DG> Having a script kick off and write to a disk will help so long as that DG> disk is writable; if it's being used as a hot spare in a raidz array, DG> it's not going to help much. For my RE2 and RE4 disks I wrote a script that calls smartctl -a on all disks (one after another) every 5s or so. This also prevents the counter to increase in my setup and you can do it for every disk, no matter if they are in a raid compound or not. I think writing to the disks may also fail the desired effect if you have stripes the writes are spead to (raid 50 or similar zpool setups). Just my 2=A2. cu Gerrit