From owner-freebsd-stable@FreeBSD.ORG Fri Sep 22 11:15:42 2006 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id F1CDF16A417 for ; Fri, 22 Sep 2006 11:15:42 +0000 (UTC) (envelope-from dmitry@atlantis.dp.ua) Received: from postman.atlantis.dp.ua (postman.atlantis.dp.ua [193.108.47.1]) by mx1.FreeBSD.org (Postfix) with ESMTP id DAF5443D67 for ; Fri, 22 Sep 2006 11:15:41 +0000 (GMT) (envelope-from dmitry@atlantis.dp.ua) Received: from atlantis.dp.ua (localhost [127.0.0.1]) by postman.atlantis.dp.ua (8.13.1/8.13.1) with ESMTP id k8MBFVED086783; Fri, 22 Sep 2006 14:15:32 +0300 (EEST) (envelope-from dmitry@atlantis.dp.ua) Received: from localhost (dmitry@localhost) by atlantis.dp.ua (8.13.1/8.13.1/Submit) with ESMTP id k8MBFV4P086773; Fri, 22 Sep 2006 14:15:31 +0300 (EEST) (envelope-from dmitry@atlantis.dp.ua) Date: Fri, 22 Sep 2006 14:15:31 +0300 (EEST) From: Dmitry Pryanishnikov To: dandee@volny.cz In-Reply-To: <00f701c6ce1a$9d9ea810$6508280a@tocnet28.jspoj.czf> Message-ID: <20060922133503.F33173@atlantis.atlantis.dp.ua> References: <00f701c6ce1a$9d9ea810$6508280a@tocnet28.jspoj.czf> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-stable@freebsd.org Subject: Re: watchdogd_flags followed by panic watchdog timeout, after reboot my rc.conf disappear 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: Fri, 22 Sep 2006 11:15:43 -0000 Hello! On Sat, 2 Sep 2006, Daniel Dvo??k wrote: > I saved my rc.conf without any doubt. I believe you, really ;) > Answear: Because rc.conf had 0 Bytes !!! > > -rw-r--r-- 1 root wheel 6174 Sep 1 XX:XX rc.conf , I do not remember > time of last modification of file. > > So the content of rc.conf was completly gone !!! Yes, because by default "/" is mounted in the following fashion: noasync Metadata I/O should be done synchronously, while data I/O should be done asynchronously. This is the default. -----------------------------------------------------^^^^^^^^^^^^^^^^^^^^ So yes, /etc/rc.conf will become empty if you're just edited it, and then, e.g., power disappears. It's a dangerous situation, because box becomes unreachable via network. To guard against it, you can just mount "/" using synchronous mode: sync All I/O to the file system should be done synchronously. I've just modified my test machine's configuration in this way: /dev/ad0s3a / ufs rw,sync 1 1 and done several times "edit /etc/rc.conf" -> "power off/on" sequence (no RESET key on box). The rc.conf is intact (while w/o "sync" it became empty after my second attempt). Note that this will further decrease FS performance for "/" (I always follow old good RELENG_4 advise NOT to turn softupdates on for "/" also). That's why /tmp and /var are separate partiotions (or just symlinks to SU-enabled /usr) in my typical setup. > And please explain me somebody, how I lost the content of rc.conf file. :-O I hope I've just managed to do that ;) > P.S.: I am not currently subscribed in the freebsd-stable mailling list, so > use my e-mail address. I am ok with freebsd-current mailling list. I think my recipe would be more useful in -stable list (which IMHO is "a must" for reading by the production machines admins), that's why I'm sending to the -stable also. Sincerely, Dmitry -- Atlantis ISP, System Administrator e-mail: dmitry@atlantis.dp.ua nic-hdl: LYNX-RIPE