From owner-freebsd-hackers@FreeBSD.ORG Thu Jul 27 19:15:15 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5EF6116A4DF for ; Thu, 27 Jul 2006 19:15:15 +0000 (UTC) (envelope-from xfb52@dial.pipex.com) Received: from smtp-out2.blueyonder.co.uk (smtp-out2.blueyonder.co.uk [195.188.213.5]) by mx1.FreeBSD.org (Postfix) with ESMTP id 20A5D43D55 for ; Thu, 27 Jul 2006 19:15:13 +0000 (GMT) (envelope-from xfb52@dial.pipex.com) Received: from [172.23.170.146] (helo=anti-virus03-09) by smtp-out2.blueyonder.co.uk with smtp (Exim 4.52) id 1G6BKC-00068L-0J; Thu, 27 Jul 2006 20:15:12 +0100 Received: from [82.41.35.166] (helo=[192.168.0.2]) by asmtp-out6.blueyonder.co.uk with esmtp (Exim 4.52) id 1G6BKB-0005b4-Am; Thu, 27 Jul 2006 20:15:11 +0100 Message-ID: <44C910BE.9000108@dial.pipex.com> Date: Thu, 27 Jul 2006 20:15:10 +0100 From: Alex Zbyslaw User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-GB; rv:1.7.13) Gecko/20060515 X-Accept-Language: en MIME-Version: 1.0 To: freebsd-hackers@freebsd.org References: <20060727063936.GA1246@titan.klemm.apsfilter.org> <20060727122159.GB4217@britannica.bec.de> <20060727134948.GA3755@energistic.com> <20060727180412.GB48057@megan.kiwi-computer.com> <17609.1474.618423.970137@bhuda.mired.org> In-Reply-To: <17609.1474.618423.970137@bhuda.mired.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: disklabel differences FreeBSD, DragonFly X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 Jul 2006 19:15:15 -0000 Mike Meyer wrote: >In <20060727180412.GB48057@megan.kiwi-computer.com>, Rick C. Petty typed: > > >>On Thu, Jul 27, 2006 at 09:49:48AM -0400, Steve Ames wrote: >> >> >>>On Thu, Jul 27, 2006 at 02:21:59PM +0200, Joerg Sonnenberger wrote: >>> >>> >>>>DragonFly disklabels allow 16 entries by default, FreeBSD still limits >>>>it to 8. That's why you can't read it directly. >>>> >>>> >>>Are there plans to bump the default up from 8? I'm honestly torn on >>>this topic whenever I install a new system. On the one hand I like >>>having a lot of discrete mountpoints to control potential usage. On >>>the other hand with drive space being so inexpensive I sometimes >>>wonder if I need to bother and can get away with very few mountpoints. >>> >>> >>I would think that cheap disk space would mean larger disks which implies >>more mountpoints ??? >> >> > >Nope. One of the historical uses of partitions was to act as firewalls >between subsystems, so that subsystem A running out of space didn't >cause subsystem B to die for lack of space. This had the downside of >making it more likely that one of the two would run out of space >because the excess space from another subsystem could only be used by >it. With cheap disk space, you overallocate by enough to give you >plenty of warning before you have to deal with the issue. You can >safely share that space, and doing so means you have to "deal with the >issue" less often. > > You assume that "running out of space" happens over time, but with some runaway process logging to a file, for example, the partition filling up will still happen without you expecting it. It might take a bit longer with a big disk, but 20 minutes instead of 5 minutes isn't much different in terms of warning. Fill /tmp or /var and many things can fail. Fill /home and it's just users who suffer a little but mail, demons etc. just carry on. A further reason to separate partitions is that dump works at the level of a partition. Different partitions may have very different backup requirements, and for those of us without huge tape drives, partitioning to a size that can be dumped on one tape makes life easier. In some environments, fewer partitions may indeed be the new norm, but in others it would not. Personally, I would like a limit of 16. It would mean that I could fit all my regular partitions inside a single slice, freeing up other slices for, for example, experimenting with 64-bit, or -current, or whatever. Bootable FreeBSD slices will be stuck at 4 for the foreseeable future - extending the number of partitions within a slice frees up slices, which are the really limited resource. I have no real idea how hard it would be to extend from 8 to 16, but if the effort required were reasonably low, then it would get my vote. --Alex