From owner-freebsd-hackers@FreeBSD.ORG Sun Jul 30 17:01:06 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 8432316A4DA for ; Sun, 30 Jul 2006 17:01:06 +0000 (UTC) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4092843D46 for ; Sun, 30 Jul 2006 17:01:06 +0000 (GMT) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (localhost [127.0.0.1]) by apollo.backplane.com (8.13.4.20060308/8.13.4) with ESMTP id k6UH13WH005888; Sun, 30 Jul 2006 10:01:04 -0700 (PDT) Received: (from dillon@localhost) by apollo.backplane.com (8.13.4.20060308/8.13.4/Submit) id k6UH13AX005887; Sun, 30 Jul 2006 10:01:03 -0700 (PDT) Date: Sun, 30 Jul 2006 10:01:03 -0700 (PDT) From: Matthew Dillon Message-Id: <200607301701.k6UH13AX005887@apollo.backplane.com> To: David Gilbert References: <20060727063936.GA1246@titan.klemm.apsfilter.org> <20060727122159.GB4217@britannica.bec.de> <20060727202528.GA14954@titan.klemm.apsfilter.org> <200607282236.k6SMaRlj089446@apollo.backplane.com> <20060729141313.GA43548@hades.panopticon> <17612.48101.830405.56113@canoe.dclg.ca> Cc: freebsd-hackers@freebsd.org, Dmitry Marakasov 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: Sun, 30 Jul 2006 17:01:06 -0000 : :>>>>> "Dmitry" == Dmitry Marakasov writes: : :Dmitry> * Matthew Dillon (dillon@apollo.backplane.com) wrote: :>> felt that 8 partitions is restrictive. My main home server has 10 :>> and the main DragonFly box has 11. :>> :>> There is another solution for FreeBSD folks, however. You *DO* :>> have four slices to play with. You can put a disklabel with 8 :>> partitions in it on each one (for 32 total). It isn't as :>> convenient, but it does work. : :Dmitry> About `lack' of partitions - don't forget that labels can be :Dmitry> nested. Just do `bsdlabel -w /dev/ad0s1e` - you'll get :Dmitry> /dev/ad0s1ea. : :Don't also forget that gpt(8) exists and seems to provide for large :numbers of partitions. It even seems to be compiled into GENERIC by :default. : :Dave. Yah, well... I'd be a bit leery of using anything more complex then a basic disklabel. The more complex the setup, the more likely that a disk crash will become unrecoverable. I had an issue a little while back with a disk crash where the OS's insistence on reading numerous sectors at both the beginning and end of the disk before 'recognizing' it as a disk prevented me from being able to access the disk at all, even when all I wanted to do was to make a disk image of e.g. '/dev/ad6' and skip over the bad sectors. It pissed me off so much I rewrote the code in DragonFly to not actually try to interpret a slice or partition table unless something needing the slice or partition table was accessed (like '/dev/ad6s1'). A linked or recursive partition table makes things all that much more fragile. Recursion isn't as big a deal as linking. Linked partition tables are a disaster waiting to happen. No thanks! -Matt Matthew Dillon