From owner-freebsd-fs@FreeBSD.ORG Sat May 19 17:19:01 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 328F316A421 for ; Sat, 19 May 2007 17:19:01 +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 E154813C45D for ; Sat, 19 May 2007 17:19:00 +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 l4JHIvDx071135; Sat, 19 May 2007 11:18:58 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <464F3178.1020909@samsco.org> Date: Sat, 19 May 2007 11:18:48 -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: <620211.71116.qm@web63014.mail.re1.yahoo.com> In-Reply-To: <620211.71116.qm@web63014.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 11:18:58 -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 17:19:01 -0000 Gore Jarold wrote: > --- Scott Long wrote: > > >> 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. > > > Thank you. Would _you_ do this with valuable data ? > Very good question =-) If you're using softupdates then any damage will have been done when the hard shutdown happens; bgfsck won't create any new damage. The biggest problem of bgfsck beyond the i/o slowness and near deadlocks that it can create (modulo the fixes that the Kostik is working on) is that if it does encounter damage that it can't fix automatically, it exits and leaves the filesystem inconsistent. So you need to keep a very close eye on your logs and check for this, then schedule downtime when it happens so you can babysit a full fsck. Scott