jerrymc at msu.edu
Thu Dec 4 07:46:41 PST 2008
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 at 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.
> These questions are all theoretical: I've only read in passing about
> dedicated mode, but the use of this would be highly specialised by
> freebsd-questions at freebsd.org mailing list
> To unsubscribe, send any mail to "freebsd-questions-unsubscribe at freebsd.org"
More information about the freebsd-questions