From owner-freebsd-questions@freebsd.org Thu Aug 26 19:39:41 2021 Return-Path: Delivered-To: freebsd-questions@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id F04FA66FB57 for ; Thu, 26 Aug 2021 19:39:41 +0000 (UTC) (envelope-from 4250.82.1d4d40001bc2a67.521bb8545b7a151bccb0e9f440b7488c@email-od.com) Received: from s1-b0c6.socketlabs.email-od.com (s1-b0c6.socketlabs.email-od.com [142.0.176.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4GwY8D43S5z3vHT for ; Thu, 26 Aug 2021 19:39:40 +0000 (UTC) (envelope-from 4250.82.1d4d40001bc2a67.521bb8545b7a151bccb0e9f440b7488c@email-od.com) DKIM-Signature: v=1; a=rsa-sha256; d=email-od.com;i=@email-od.com;s=dkim; c=relaxed/relaxed; q=dns/txt; t=1630006781; x=1632598781; h=content-transfer-encoding:content-type:mime-version:references:in-reply-to:message-id:subject:to:from:date:x-thread-info; bh=s3chGYQ3gU0ZJM4WzXzpRnUrVQwRskFAzL0yfa03D/E=; b=ZcUSCENXARbl8twwTZZ3ZPt4EJZixqlLzl0JfLQLOMdftYPlKu/JHhjcYJnmDARzac5B8MOk7UO9EPz8kXn+5LN6B1ZvouwSDvKpzNe3FKQ3VXmXmIsfXqb2SfnMCk/6OkPs+pqLWLeWMMj0GnhxxkKTk4ubMnmDy0m18c5HZVk= X-Thread-Info: NDI1MC4xMi4xZDRkNDAwMDFiYzJhNjcuZnJlZWJzZC1xdWVzdGlvbnM9ZnJlZWJzZC5vcmc= Received: from r2.sg.in.socketlabs.com (r2.sg.in.socketlabs.com [142.0.179.12]) by mxsg2.email-od.com with ESMTP(version=Tls12 cipher=Aes256 bits=256); Thu, 26 Aug 2021 15:39:23 -0400 Received: from smtp.lan.sohara.org (EMTPY [185.202.17.215]) by r2.sg.in.socketlabs.com with ESMTP(version=Tls12 cipher=Aes256 bits=256); Thu, 26 Aug 2021 15:39:22 -0400 Received: from [192.168.63.1] (helo=steve.lan.sohara.org) by smtp.lan.sohara.org with smtp (Exim 4.94 (FreeBSD)) (envelope-from ) id 1mJLDe-000Og7-6p for freebsd-questions@freebsd.org; Thu, 26 Aug 2021 20:39:21 +0100 Date: Thu, 26 Aug 2021 20:39:21 +0100 From: Steve O'Hara-Smith To: freebsd-questions@freebsd.org Subject: Re: Paritioning scheme on MBR disk doubts Message-Id: <20210826203921.0d3537684706867aef1e30f9@sohara.org> In-Reply-To: References: X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; amd64-portbld-freebsd12.1) X-Clacks-Overhead: "GNU Terry Pratchett" Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 4GwY8D43S5z3vHT X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=email-od.com header.s=dkim header.b=ZcUSCENX; dmarc=none; spf=pass (mx1.freebsd.org: domain of 4250.82.1d4d40001bc2a67.521bb8545b7a151bccb0e9f440b7488c@email-od.com designates 142.0.176.198 as permitted sender) smtp.mailfrom=4250.82.1d4d40001bc2a67.521bb8545b7a151bccb0e9f440b7488c@email-od.com X-Spamd-Result: default: False [-2.70 / 15.00]; MID_RHS_MATCH_FROM(0.00)[]; ARC_NA(0.00)[]; R_DKIM_ALLOW(-0.20)[email-od.com:s=dkim]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; FROM_HAS_DN(0.00)[]; MV_CASE(0.50)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; TO_DN_NONE(0.00)[]; DMARC_NA(0.00)[sohara.org]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_HAM_LONG(-1.00)[-1.000]; RCVD_COUNT_THREE(0.00)[4]; R_SPF_ALLOW(-0.20)[+ip4:142.0.176.0/20]; DKIM_TRACE(0.00)[email-od.com:+]; NEURAL_HAM_SHORT(-1.00)[-1.000]; FORGED_SENDER(0.30)[steve@sohara.org,4250.82.1d4d40001bc2a67.521bb8545b7a151bccb0e9f440b7488c@email-od.com]; RWL_MAILSPIKE_POSSIBLE(0.00)[142.0.176.198:from]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_LAST(0.00)[]; ASN(0.00)[asn:7381, ipnet:142.0.176.0/22, country:US]; FROM_NEQ_ENVFROM(0.00)[steve@sohara.org,4250.82.1d4d40001bc2a67.521bb8545b7a151bccb0e9f440b7488c@email-od.com]; MAILMAN_DEST(0.00)[freebsd-questions]; DWL_DNSWL_NONE(0.00)[email-od.com:dkim] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Aug 2021 19:39:42 -0000 On Thu, 26 Aug 2021 15:36:12 +0200 Javier wrote: > Let me ask in schematic way :) (Questions in the middle) > > Note: my original idea was to post this on the forum but formatting > capabilities... didn't help. > > Anyway..., sorry the verbosity. > > I guess we all agree (terminology correctness aside) with the > following two examples: > -------------- > 1) DOS|GNU/Linux > > MBR > +---Primary/Extended* 1 > +---Primary/Extended* 2 > +---Primary/Extended* 3 > +---Primary/Extended* 4 > (if Extended) > +---Logic 1 > +---Logic 2 > +---. > +---. > +---. > +---Logic nth Yep - except IMSC n is no more than 4. > 2) DOS|GNU/Linux + FreeBSD > > MBR > +---Primary/Extended* 1 > +---Primary/Extended* 2 > +---Primary/Extended* 3 > ¦ (if Extended) > ¦ +---Logic 1 > ¦ +---Logic 2 > ¦ +---. > ¦ +---. > ¦ +---. > ¦ +---Logic nth > +---FreeBSD 4 (Slice) > +---Partition 1 > +---Partition 2 > +---Partition 3 > +---. > +---. > +---Partition (h/eight/8?) This the standard way of installing FreeBSD on an MBR based system - FreeBSD docs call the MBR partitions slices because they wanted to keep the partition name as used on other platforms. > ****** Being the FreeBSD slice on any position of the 4 MBR > possible options. Just placed 4th for simplicity in the scheme Indeed. > Ok, now the third example, where I mixed cases, so some questions > in one. > > Can a whole FreeBSD installation (mountpoints) be spread along > multiple slices? Yes but the installer won't be much help. > Can I have more than h/eight/8 partitions when using more than one > slice? If no, why this small limit? Yes because each slice would contain a BSD Disklabel with up to eight partitions. > Can mountpoints be outside of slices? Specially or > specifically, /boot. Can it be on a FAT/32 or ext/2/3/4 file system /boot I'm pretty sure has to be UFS or ZFS because that's what the bootloader (very small code) can read. > outside the slices? I understand any other should be inside the > FreeBSD slices only. > > And when I say slices, I don't mean only on one disk, but several too. Yes you can spread things over multiple disks, once upon a time it tended to be necessary for capacity. > -------------- > 3) DOS|GNU/Linux + FreeBSD (hypothetical case) > > MBR > +---Primary/Extended* 1 /Boot > +---FreeBSD 2 (Slice) > ¦ +---Partition 1 /etc > ¦ +---Partition 2 /home > ¦ +---Partition 3 > ¦ +---. > ¦ +---. > ¦ +---Partition (h/eight/8?) > +---Primary/Extended* 3 > ¦ (*if Extended and only one) > ¦ +---Logic 1 > ¦ +---Logic 2 > ¦ +---. > ¦ +---. > ¦ +---. > ¦ +---Logic nth > +---FreeBSD 4 (Slice) > +---Partition 1 / > +---Partition 2 > +---Partition 3 > +---. > +---. > +---Partition (h/eight/8?) /swap > -------------- Unless MBR has changed since I last looked there could only be one extended partition(slice) and it had to be the fourth. Other than that this should work. One more option (that you probably don't want), you can put a BSD disklabel on the whole disc and not have an MBR or GPT at all - this is called Dangerously Dedicated. I mention this only for completeness. > Despite I ask for MBR scheme, that is my BIOS/Disk system, I guess > answers should be applicable to GPT, more or less, with its > differences. GPT is *much* simpler if you want lots of partitions - there's just one level and you can have as many as you like. No partition/slice confusion, no BSD disklabels, no extended partitions just a bunch of partitions with names that you provide. MBR is considered obsolete and GPT the replacement. Highly recommend using GPT if all the OSs can use it. -- Steve O'Hara-Smith