From owner-freebsd-fs@FreeBSD.ORG Sat May 19 06:32:33 2007 Return-Path: X-Original-To: freebsd-fs@freebsd.org Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 072BF16A400 for ; Sat, 19 May 2007 06:32:33 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.freebsd.org (Postfix) with ESMTP id B1FF513C4AD for ; Sat, 19 May 2007 06:32:32 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from phobos.samsco.home (phobos.samsco.home [192.168.254.11]) (authenticated bits=0) by pooker.samsco.org (8.13.8/8.13.8) with ESMTP id l4J6WSjN068178; Sat, 19 May 2007 00:32:29 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <464E99F3.3000602@samsco.org> Date: Sat, 19 May 2007 00:32:19 -0600 From: Scott Long User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.2pre) Gecko/20070111 SeaMonkey/1.1 MIME-Version: 1.0 To: Gore Jarold References: <550589.3257.qm@web63006.mail.re1.yahoo.com> In-Reply-To: <550589.3257.qm@web63006.mail.re1.yahoo.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-2.0.2 (pooker.samsco.org [168.103.85.57]); Sat, 19 May 2007 00:32:29 -0600 (MDT) X-Spam-Status: No, score=-1.4 required=5.5 tests=ALL_TRUSTED autolearn=failed version=3.1.8 X-Spam-Checker-Version: SpamAssassin 3.1.8 (2007-02-13) on pooker.samsco.org Cc: freebsd-fs@freebsd.org Subject: Re: dangers of delaying an fsck on busy fileserver ? 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, 19 May 2007 06:32:33 -0000 Gore Jarold wrote: > I have a busy fileserver - 5-20 sftp/rsync processes > running on it at all times. > > For unknown reasons, this server crashes in the middle > of the night sometimes. When it does, I comment out > my four big arrays in /etc/fstab, reboot, and fsck > them manually (without a snapshot and BG fsck). > > Easy. The problem is, I need to sit around and wait > for an fsck in the middle of the night and then > re-edit fstab and reboot. > > So I am curious ... what happens if I instruct the NOC > tech to just press the reset switch instead of calling > me ? If he does this, the system will boot, the > arrays will come online, and since I have a very very > long time set until bg_fsck starts, I can then reboot > the machine and foreground fsck it during sunlight > hours. > > But it does mean that users will continue to operate > on those dirty disks for 4-8 hours until I do that. > > Is this a dangerous strategy ? > > Does this put me at some increased risk of finding > myself with disks that cannot be fsck'd ? (I've never > seen it, but I have heard horror stories...) > > Will I lose a lot of the data that has been transacted > during the hours that the disks were used in a dirty > state ? > > Any comments ? > In an ideal world, the only consequence of delaying bgfsck is that not all filesystem blocks will be marked free that should be. So if you deleted a large tree of files before the crash, those blocks might still show up in use until bgfsck completes. Scott