Date: Tue, 1 Sep 1998 09:11:29 +0930 From: Greg Lehey <grog@lemis.com> To: "Robert D. Keys" <bsdbob@seedlab1.cropsci.ncsu.edu>, freebsd-questions@FreeBSD.ORG Subject: Re: Looking for logic and rationale of fs partition conventions. Message-ID: <19980901091129.U606@freebie.lemis.com> In-Reply-To: <199808311601.MAA13179@seedlab1.cropsci.ncsu.edu>; from Robert D. Keys on Mon, Aug 31, 1998 at 12:01:08PM -0400 References: <199808311601.MAA13179@seedlab1.cropsci.ncsu.edu>
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On Monday, 31 August 1998 at 12:01:08 -0400, Robert D. Keys wrote: > Can anyone fill me in (and probably others too), as to the logic and > rationale of the fs partition naming conventions of BSD from 4.3, > Tahoe, Reno, 4.4, 4.4-Lite, and FreeBSD? We tend to call them slices instead of partitions in order to avoid some of the confusion of them being stored in Microsoft partitions. > I understand ``a'' is the root partition, ``b'' the swap partition, > and ``c'' the entire disk. After that, d/e/f/g/h sort of go every > which way, with no particular rhyme or reason. ``g'' is often used > for the remaining /usr partition, but there does not seem to be much > clear reasoning as to why. I would like to understand that rhyme > and reason. You were right first time. There is neither rhyme nor reason. They're just 5 slices you can use any way you like. In fact, slice 'a' is pretty much the same except on the first disk, and 'b' is just a convention. The only slice the system knows about and gives special treatment to is 'c'. Having said that, 'd' used to imply the whole Microsoft partition, so FreeBSD used to (maybe still does?) start allocating additional slices with slice 'e'. BSD/OS started at 'h' and worked backwards. None of this is so important, though. > Also, what is the convention of fs splitting between drives? The > table in the 4.4SMM (sec. 2.5.2) suggests some possiblities, but is > there any other rationale behind the choices? How things might be > affected loadwise on singleuser workstations vs heavy servers, is > probably very different. I would like to understand more of the > reasoning of these conventions. The text in SMM goes into more detail: the main concern is to balance the load between the disks. When this was written, a big disk was 1 GB. Now you can't get anything that small any more, and the rules have changed. Most people only have one disk, mainly 2. Under those circumstances, you probably want as few slices as possible. I have always recommended one file system per disk, with the exception of the system disk, which can contain a root file system as well as the /usr file system (and swap space). Others disagree and bring forward arguments for a /var file system, but that only makes sense if you're going to try to make /usr read-only, which almost nobody does. Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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