Disk Partitions under Sys V/386

[Ted Powell]

In article <598 at gistdev.UUCP> joe at gistdev.UUCP (Joe Brownlee) writes:
>I have a 6386 WGS on which I am about to install UNIX System V/386, version
>3.2.  The machine has two disk drives: a 72 MB and a 40 MB drive.  I wish to
>place partitions on the disks such that /, swap, and a /usr2 partition are
>on the first disk (the 72 MB), and /usr is on the 40 MB.  OK, so far.
>
>The problem seems to be that when you are installing UNIX, the installation
>software only knows about the first disk.  Since this is the case, it insists
>that /, swap, and /usr all be placed on the same disk.  You can add the second
>disk using FACE later, but you have to have the machine up under UNIX first.

I would say, keep the install script happy; lie to it. Let it believe
you really _want_ /, swap, and /usr on the first disk. But for the size
of /usr, tell it the size you're going to want /usr2 to be. (This only
works, of course, if your desired size for /usr2 is big enough for the
install script to put everything in that it wants.) Follow the normal
install procedure until you've got the base system and the editing
package installed. Make sure you can use vi at this point; the terminfo
file for the console (AT386) should be installed by now. Of course, you
could install the whole system at this point, it's just that if you
follow the procedure below and it (heaven forbid!) doesn't come out
quite right, you've got less time invested. Come to think of it, you're
going to have to install enough stuff so that you can have FACE set up
the second disk as /usr2 and whatever else. Make /usr2 whatever size
you're going to want /usr to be (likely the whole disk).
    Caveat: I've never added a second disk to a 6386WGS (to a MicroVax
II, yes, but that's another story...). However, I _have_ shuffled
partitions on a single (300mb) disk a couple of times, most recently
this afternoon.
    At this point, you should have /usr (on the first disk) all set up
with all kinds of good stuff in it, and /usr2 (on the second disk) with
nothing in it except probably a directory called lost+found; we want
to get everything that's in /usr into /usr2, flip their names around,
and finally delete everything out of the partition on the first disk
(except lost+found).
    Log in as root. Check the file /etc/fstab. It should have two lines
in it, associating /dev/dsk/0s3 with /usr and /dev/dsk/1swhatever with
/usr2. Later we'll be flipping these, so it's good to know they are
there (the second line should have been added when you added the second
disk). 
    Go into "single-user" mode; you don't want things shifting around
underfoot. Do this with:
    cd /; shutdown -g0 -y -is
You will need to give the root password to get into maintenance mode or
whatever they call it (you'll be prompted for it).
    Caveat again: Check all this against your manuals. I'm typing this
from notes I made this afternoon, but I'll be changing it slightly to
match (my perception of) your circumstances, and I can't promise it will
be typo-free.
    Once you are in single user/maintenance mode, make sure your path
and TERM are ok. Do:
    PATH=/bin:/etc:/usr/bin
    TERM=AT386
    export PATH TERM
Make sure both /usr and /usr2 are mounted by doing:
    mountall
Check that you can run vi. Try vi /etc/fstab, but don't change anything
at this time.

Now for the big copy. Do:
    cd /usr
    find . -depth -print | cpio -padlmv /usr2
This will take a while, depending how much stuff is in /usr. You'll find
this given as an example at the end of the manual page for CPIO(1),
except that I've added the -a option to preserve access times as well.
This way of doing the copy preserves just about everything. There's an
example in TAR(1) of doing the copy with a couple of tar's, but (for
SVR3.2v2.1 on 6386WGS) it was my experience that directory attributes
didn't come out right. During the time I was wrestling with this a
couple of weeks ago on a different 6386, I also tried COPY(1), but was
also dissatisfied with that, for reasons that I may or may not have
written down somewhere.
    Meanwhile, back at the system, you should have built yourself an
exact copy (ownerships, permissions, and all) of /usr on /usr2. Make
sure that /usr2/lost+found is ok; if cpio overwrote it with a copy of
the one from /usr (I'm not sure if it would, since what I did didn't
entail copying lost+found), then the new version should be the same size
as before (i.e. not truncated to 32 bytes). Do some spot checks to
satisfy yourself that /usr2 is now a duplicate of /usr.

Now we do the swap. The partitions need to be unmounted before you can
change their names. You can unmount everything in /etc/fstab (which
should be just /usr and /usr2) by doing:
    cd /
    umountall
The cd to / is because the current directory was /usr, which would have
prevented you from unmounting it. To label /usr and /usr2 the other way
around:
    labelit /dev/dsk/0s3 usr2 disk0
    labelit /dev/dsk/1s1* usr disk1  # *get the correct designation
				     # of this partition from /etc/fstab
Make sure you don't use the option flag to labelit which causes it to
wipe the partition (I'm not mentioning the option letter; you don't need
_any_ option letters for a name change). Replace the device designation
in the second labelit command with whatever is correct for the partition
on the second disk that was /usr2 and is becoming /usr.
    Edit /etc/fstab and change /usr to /usr2, /usr2 to /usr. Check it
twice. Do:
    mountall
which should go without any fuss. Now /usr should reference the second
disk, with all the files you copied there, and /usr2 should reference
the first disk, with the files put there by the install process.
    Once you're satisfied that everything is as it should be, you want
to remove the files under what is now /usr2 (on the first disk). You can
do this, for example, with:
    cd /usr2
    rm -rf <all the entries in /usr2 except lost+found>
or if you want to save on typing, try this first with something like
'echo' instead of 'rm -rf':
    cd /usr2
    rm -rf `ls | grep -v lost+found`
Now you should have nothing but lost+found in /usr2 (on the first disk)
and in /usr (on the second disk) you should have an exact copy of what
you originally installed on the first disk's /usr.

Now reboot. Do:
    shutdown -g0 -y
and hit the reset button rather than going straight from single user
state to multiuser state; the latter, in my experience, doesn't start
the printer scheduler (SVR3.2v2.1 for AT&T 6386WGS).

If neither of us made any typos, your /usr and /usr2 should now be where
you want them.  Good luck, and remember your mileage may vary!    :-)

(In my case, what I was doing was moving the stuff under /usr/u (i.e.
all the users' files) to a partition which used to be /usr2. The latter
is now called 'u' and mounts on the directory /usr/u.)
-- 
ted at eslvcr.wimsey.bc.ca   ...!ubc-cs!van-bc!eslvcr!ted    (Ted Powell)