From owner-freebsd-stable@FreeBSD.ORG Thu Feb 23 07:03:00 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 B2A1B16A420 for ; Thu, 23 Feb 2006 07:03:00 +0000 (GMT) (envelope-from peterjeremy@optushome.com.au) Received: from mail17.syd.optusnet.com.au (mail17.syd.optusnet.com.au [211.29.132.198]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0567A43D45 for ; Thu, 23 Feb 2006 07:02:07 +0000 (GMT) (envelope-from peterjeremy@optushome.com.au) Received: from turion.vk2pj.dyndns.org (c220-239-19-236.belrs4.nsw.optusnet.com.au [220.239.19.236]) by mail17.syd.optusnet.com.au (8.12.11/8.12.11) with ESMTP id k1N715rl001027 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Thu, 23 Feb 2006 18:01:06 +1100 Received: from turion.vk2pj.dyndns.org (localhost.vk2pj.dyndns.org [127.0.0.1]) by turion.vk2pj.dyndns.org (8.13.4/8.13.4) with ESMTP id k1N715o5000948; Thu, 23 Feb 2006 18:01:05 +1100 (EST) (envelope-from peter@turion.vk2pj.dyndns.org) Received: (from peter@localhost) by turion.vk2pj.dyndns.org (8.13.4/8.13.4/Submit) id k1N705le000947; Thu, 23 Feb 2006 18:00:05 +1100 (EST) (envelope-from peter) Date: Thu, 23 Feb 2006 18:00:05 +1100 From: Peter Jeremy To: Miguel Lopes Santos Ramos Message-ID: <20060223070005.GA688@turion.vk2pj.dyndns.org> References: <28a99ba50602212307g48db9a53m322fba44eb315a17@mail.gmail.com> <200602221003.k1MA3ixi001559@compaq.anjos.strangled.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200602221003.k1MA3ixi001559@compaq.anjos.strangled.net> X-PGP-Key: http://members.optusnet.com.au/peterjeremy/pubkey.asc User-Agent: Mutt/1.5.11 Cc: rossiya@gmail.com, freebsd-stable@freebsd.org Subject: Re: Remote tunefs -n enable 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: Thu, 23 Feb 2006 07:03:00 -0000 On Wed, 2006-Feb-22 10:03:44 +0000, Miguel Lopes Santos Ramos wrote: >> From: MC >> Consequently he hasn't set softupdates on the main '/' partition > >It wasn't his fault. It is the default install option. >You see, root is mainly a read file system. Typical writes are a kernel >install (not too important to optimize) and updating configuration files >(it shouldn't be so often). The real reason is that there is a "bug" in softupdates which means that space freed up by deleting a file is not available for allocation for about 30 seconds. (Fixing this is non-trivial). The root file- system is traditionally relatively small and a substantial portion of it is re-written during installworld and installkernel, leading to a non-trivial likelihood that you could get a false "filesystem full" message. >Furthermore, if one can avoid any risky operation on /, all the better. >I think that's why the option for / is using synchronous writes without Actually, / uses traditional Unix semantics - synchronous metadata updates (inodes and directories) and asynchronous data updating. >I think the filesystem must be unmounted to enable softupdates. One approach would be to stick a script into /etc/rc.d that executes early (before root is made R/W) to run "tunefs -n enable ..." and then delete the script after rebooting. -- Peter Jeremy