From owner-freebsd-stable@FreeBSD.ORG Sun Jan 24 22:55:20 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 9D68D1065672 for ; Sun, 24 Jan 2010 22:55:20 +0000 (UTC) (envelope-from aragon@phat.za.net) Received: from mail.geek.sh (decoder.geek.sh [196.36.198.81]) by mx1.freebsd.org (Postfix) with ESMTP id 361C88FC0C for ; Sun, 24 Jan 2010 22:55:19 +0000 (UTC) Received: from igor.geek.sh (unknown [196.209.245.239]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mail.geek.sh (Postfix) with ESMTPSA id 78DC639888 for ; Mon, 25 Jan 2010 00:38:17 +0200 (SAST) Message-ID: <4B5CCBDA.3090403@phat.za.net> Date: Mon, 25 Jan 2010 00:38:18 +0200 From: Aragon Gouveia User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.9.1.5) Gecko/20100109 Thunderbird/3.0 MIME-Version: 1.0 To: freebsd-stable@freebsd.org References: <4B54C100.9080906@mail.zedat.fu-berlin.de> In-Reply-To: <4B54C100.9080906@mail.zedat.fu-berlin.de> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit 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: Sun, 24 Jan 2010 22:55:20 -0000 On 01/18/10 22:13, O. Hartmann wrote: > Symptome: All boxes have ZFS and UFS2 filesystems. Since two weeks or > so, sometimes the I/O performance drops massively when doing 'svn > update', 'make world' or even 'make kernel'. It doesn't matter what > memory and how many cpu the box has, it get stuck for several seconds > and freezing. On the UP box, this is sometimes for 10 - 20 seconds. > A very interesting phenomenon is the massively delayed file writing on > ZFS filesystems I realise. Editing a file in 'vi' running on one XTerm > and having in another Xterminal my shell for compiling this file, it > takes sometimes up to 20 seconds to get the file updated after it has > been written. It's like having an old, slow NFS connection with long > cache delays. > These massively delayed file transactions are not necessarely under > heavy load, sometimes they occur in a relaxed situation. They seem to > occur much more often on the UP box than on the SMP boxes, but this > strange phenomenon also occur on the Dell Poweredge II, which has 16GB > RAM and summa summarum 16 cores. This phenomenon does occur on ZFS- and > UFS2 filesystems as well. It is hardly reproducable. I'm experiencing the same thing, except in my case it's most noticeable when writing to a USB flash drive with a FAT32 filesystem. It slows the entire system down, even if the data being written is coming from cache or a memory file system. I don't know if it's related. I'm running 8-STABLE from about 4 December. Regards, Aragon