Date: Thu, 4 Dec 2008 10:41:36 -0500 From: Jerry McAllister <jerrymc@msu.edu> To: Da Rock <rock_on_the_web@comcen.com.au> Cc: freebsd-questions@freebsd.org Subject: Re: UFS partitioning Message-ID: <20081204154136.GA1366@gizmo.acns.msu.edu> In-Reply-To: <1228355243.23645.10.camel@laptop1.herveybayaustralia.com.au> References: <Pine.GSO.4.63.0812021048180.3801@hmacs.cmi.ua.ac.be> <20081202111740.96805018.freebsd@edvax.de> <20081202163920.GE90039@gizmo.acns.msu.edu> <1228355243.23645.10.camel@laptop1.herveybayaustralia.com.au>
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On Thu, Dec 04, 2008 at 11:47:23AM +1000, Da Rock wrote: > > On Tue, 2008-12-02 at 11:39 -0500, Jerry McAllister wrote: > > On Tue, Dec 02, 2008 at 11:17:40AM +0100, Polytropon wrote: > > > > > On Tue, 2 Dec 2008 10:56:44 +0100 (CET), Pieter Donche <Pieter.Donche@ua.ac.be> wrote: > > > > If FreeBSD is to put on the system as only operating system (Fdisk: > > > > "A = Use Entire disk"), then will the BSD-partitions will show up as > > > > ad0a (/), ad0b (swap), ad0d (/var) etc... correct or not (then what)? > > > > > > You're mixing terminology here. :-) The "use entire disk" will > > > create a slice for FreeBSD covering the complete disk. A slice > > > is what MICROS~1 calls "primary partition". > > > > > > Now the conclusion: Let's say you create a slice on ad0, it will > > > be ad0s1. Now you can create partitions inside this slice as you > > > mentioned it, e. g. ad0s1a = /, ad0s1b = swap, ad0s1d = /tmp, > > > ad0s1e = /var, ad0s1f = /usr and ad0s1g = /home. > > > > True. Too bad MS had to use the same terminology for slices > > as FreeBSD uses for subdivisions of slices. But, it won't be > > undone now, so the confusion will continue. > > > > > But if you're > > > refering to ad0a, ad0b, ad0d etc. you're stating that there's > > > no slice, implying that (if I see this correctly) it isn't possible > > > to boot from that disk. > > > > It is correct that this would imply no slice being created. > > But it is not correct that it could not be bootable. You can > > use bsdlabel to write the boot sector to ad0 instead of ad0s1 > > and it would be bootable - but would be what someone has enjoyed > > describing as a 'dangerously dedicated' disk. FreeBSD can deal > > with it, but other systems cannot. > > > > I don't know if you can do this from sysinstall though. I have > > never tried. But, it can be done by running bsdlabel by hand. > > > > > Of couse, if you would intend to use > > > a (physical) second disk for only the home partition, you could > > > omit the slice and the partition and simply newfs ad1 - but > > > that wasn't your question. > > > > Probably the 'dangerously dedicated' disk is more often used this > > way as an additional (second) drive that is not made bootable. > > > > In that case, it is unlikely that one would mount any of the > > partitions on '/' making it the root filesystem. That may > > be a problem. But, otherwise this looks probable or more likely > > it would have some swap to add to the first disk and all the > > rest in either the a or d partitions mounted as something > > like '/work' or /scratch'. > > > > > > > > ad0 |-----------------------------------------------| the whole disk > > > ad0s1 \----------------------------------------------/ one slice > > > ad0s1X \--/\---/\-----/\-----/\-------/\------------/ partitions > > > a b d e f g > > > / swap /tmp /var /usr /home mount point > > Excuse my nose in here- I just have a couple of questions. > > 1) It IS possible to boot from a dedicated disk? Yes, as described above. > 2) Does using dedicated mode increase the space available to use? > Partitioning normally takes up space so a HDD loses about 10% of usable > space doesn't it, so the space used by partitioning is can now be used > as filespace. No. Slicing and Partitioning take up negligible space. Building a file system on the disk/slice/partition takes up a chunk. The most is taken up by an 8% (by default) reserve that is held back for root use when a file system is built. ////jerry > > These questions are all theoretical: I've only read in passing about > dedicated mode, but the use of this would be highly specialised by > extension. > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org"
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