From owner-freebsd-questions@freebsd.org Sun Aug 30 15:39:39 2020 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 353583BF163 for ; Sun, 30 Aug 2020 15:39:39 +0000 (UTC) (envelope-from freebsd@edvax.de) Received: from mout.kundenserver.de (mout.kundenserver.de [217.72.192.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "mout.kundenserver.de", Issuer "TeleSec ServerPass Class 2 CA" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Bfcvt1851z45Yv for ; Sun, 30 Aug 2020 15:39:37 +0000 (UTC) (envelope-from freebsd@edvax.de) Received: from r56.edvax.de ([178.12.112.48]) by mrelayeu.kundenserver.de (mreue106 [212.227.15.183]) with ESMTPA (Nemesis) id 1M5PVb-1kDEuA48Gb-001S3W; Sun, 30 Aug 2020 17:39:28 +0200 Date: Sun, 30 Aug 2020 17:39:25 +0200 From: Polytropon To: "@lbutlr" Cc: FreeBSD Subject: Re: (very OT) Ideal partition schemes (history of partitioning) Message-Id: <20200830173925.3d340cfb.freebsd@edvax.de> In-Reply-To: References: Reply-To: Polytropon Organization: EDVAX X-Mailer: Sylpheed 3.1.1 (GTK+ 2.24.5; i386-portbld-freebsd8.2) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K1:no7PXZM2txqdWyGCSvAZ5iPfo9PXTV26yN49GqERt3RTFIObKPu kiiEoX5t4Y9OUnRoBwwDczePMBZx+6rmbDmpRGJk5zzRuCf6D8yRFs+a0slWxuZjM72jcmI tmZF/FCSIYz1xFzCIK9g322qt4qGmvObnBp5G2JxkcJkZ+Uj+AHUu98DJgFXKJCIxZsK//G aH4sURmhQ4W8/Zhuaf3mQ== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:eapAv4in2no=:B+XFj0B5lqrqPyTh4rX/AP uMsmQi9rBFtxa62Nwp1Xh1zZWR/dDhfdzJH5q5Gt5Kj5A4No5g9jD+5uqcc+XGSk0Q9b/JxPS bDs7zqw18nizetb3mA6qhi0cPtKR133+BrjnmhaC9y17r77ZmdcqIR270JO3eThIFjaWoMQpO DzzETIP+dFtzv9/QwuQI32l+sLzP4EfJbxfxpfxvYXIVKjxnfUZry+ZW40kp+3+/m567mOXar smJ5h1LCScm7R3mF+Wgayb37mL1PNVuJuPTf00HEc6XlPXnkaUsCknCxo0YHnXXl8ojjNdF+z CmoAEv24NJFdbP6QYgHOjlgdVjCDJ45OVn44zmPce39DN+TWYlfKB7q8HsECGw5+TCmN72Nrm 7bYqwxVrReVq59beOFl91R5CPIqloFJJsUGkw835iqQV9V3nkPceybmt9nZZRcj7kNy4zF0N4 r4ZpsK2AbyJL6a/V4cBsIBgwXHFTS95gfNuo0YnZn1ghR0HTCb7tiTuRpBqtuM2aZs66rVJKS KII3DpjJpMQwnqoqUklj3l90BA0ADrhAV0O/Zsmjcmn0M26k65LLiCfTI3I5NDa7JpLt6Xf7f nVWvONarNnPbY9qw5GWhArM5nwWaTLpXWs2u6xkY0NNJZrLBspvMKXVlVhomaQu0tnPPvejHk inC5VvK+Myp7nXNI7Ox0aVuv2JBfRtFIuSUPGU9uDO0pC/s0dqAw9Fi08eaGvHjKY/n4x5JaU Qd90dCCE7rqXerW0Zg2Ix/42akwik/UnP1KyOFOpY4lpDS/kF2ty9bOopexuaFXigaJGglcmz zAuaPNqIXGFplOrd75Nji2X5iJPbryO4Sj41BqOfEaPOMdm4/PphvLADAtwve8WkxeXDrf1 X-Rspamd-Queue-Id: 4Bfcvt1851z45Yv X-Spamd-Bar: +++ Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=none (mx1.freebsd.org: domain of freebsd@edvax.de has no SPF policy when checking 217.72.192.74) smtp.mailfrom=freebsd@edvax.de X-Spamd-Result: default: False [3.44 / 15.00]; HAS_REPLYTO(0.00)[freebsd@edvax.de]; RCVD_VIA_SMTP_AUTH(0.00)[]; MV_CASE(0.50)[]; HAS_ORG_HEADER(0.00)[]; TO_DN_ALL(0.00)[]; RCPT_COUNT_TWO(0.00)[2]; RECEIVED_SPAMHAUS_PBL(0.00)[178.12.112.48:received]; RCVD_TLS_LAST(0.00)[]; R_DKIM_NA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:8560, ipnet:217.72.192.0/20, country:DE]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-0.08)[-0.076]; REPLYTO_EQ_FROM(0.00)[]; FROM_HAS_DN(0.00)[]; NEURAL_SPAM_SHORT(0.42)[0.425]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[edvax.de]; AUTH_NA(1.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; NEURAL_SPAM_LONG(0.69)[0.694]; MID_CONTAINS_FROM(1.00)[]; RCVD_IN_DNSWL_NONE(0.00)[217.72.192.74:from]; R_SPF_NA(0.00)[no SPF record]; RWL_MAILSPIKE_POSSIBLE(0.00)[217.72.192.74:from]; RCVD_COUNT_TWO(0.00)[2]; MAILMAN_DEST(0.00)[freebsd-questions] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Aug 2020 15:39:39 -0000 On Sun, 30 Aug 2020 04:18:48 -0600, @lbutlr wrote: > On 28 Aug 2020, at 21:08, Aryeh Friedman wrote: > > Also why are partitioned need at all? (both currently and historically) > > They are not needed now, and I don't think they provide any benefit, really. This is actually what "dedicated" means: no MBR, no GPT, just labels. And you are correct: Only _one_ label (i. e., one partition which is, in fact, no partition / slice) is required: the 'a' partition, defining it as a boot partition. For a single-OS install of FreeBSD this is possible. Now you might say: what about swap? No separate swap partition? You can use memory-backed or file-backed swap. Yes, all this has several restrictions and limitations, but from a purely technical point of view, it's absolutely possible. By the way, I do the same on "fill & stack" data disks: They only get one UFS filesystem directly to the device, no partitioning at all: "newfs /dev/da0" - and it can be used. Sure, it does not boot, but data disks _don't_ boot. Can they be read in "Windows"? No, but FreeBSD data disks aren't read outside of FreeBSD. In this special case, only /dev/da0c (which equals /dev/da0) is created, and you can mount it as "mount -t ufs /dev/da0 /mnt". > Sure, you can do a multiple OS setup on a single drive with > partitions, but this is quite risky if Windows is involved which > is the main reason people want to do this. It's better to have > separated physical drives. That's often not as easy, especially when you use a laptop. But in such cases, it's sometimes more secure to use external USB (usually USB-C for better speed), to keep your regular workstation out of risk (at least try to). The problem with multiple systems on one disk is that they might not be able to boot from anything than a slice (a "DOS primary partition"), and there can only be up to 4 of them. Let's say you also need a boot manager - 1 slice gone, 3 remaining. One for FreeBSD, one for Linux, one for "Windows". If you need more, for example, if you want to have a dedicated data exchange partition or "shared /home", you will probably see "DOS extended partitions" and the "logical volumes" inside them as a possible solution. That might work for data, or subsequently mounted partitions (for example, if you have Linux and want to separate /usr, /var, /tmp, and such), but in most cases, those cannot hold a OS to _boot_ from, not because it wouldn't be possible to tell GRUB to load from that device (GRUB doesn't care, it just transfers control), but because the OS might expect to be run from a _primary_ partition and simply refuse to boot. Also note that in traditional DOS partitioning, only one of the 4 partitions can be marked "active", which indicates a bootable partition, and BIOS systems will tend to boot from the first one they find. Furthermore, this approach is quite static and does not easily allow to switch systems - that's where GRUB (or any other suitable boot manager for that matter) is the most useful part. > Historically they were quite important because partitions could > fail without the disk failing, and restoring a partition is > obviously much faster than restoring a whole drive. That is the reason why the programs dump and restore exist: They process data partition-wise (not at file level), so any VFS overhead can be avoided. Linear reads and writes are also an advantage if your backup media is sequencial access, such as tape. Backups were quite common, partially automated, scheduled, and required, so in case of severe drive problems, you loaded a new disk pack and restored from yesterday's tape backup. You are right - this is _not_ what people do today. :-) -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...