Very Computer

Now I want to install a fair amount of software onto the machine and
want to rename /shared to /usr. Can I just move everything from the
existing /usr to /shared, rename it in /etc/fstab or do I need to
carefully unmount each filesystem and then remount them? I will be
really happy if I can do this without rebooting :-)

Thanks for your time.
Ryan

--
Help! Windows has fallen and it can't get up!

A warning, some applications might compile and install into /usr/local
meaning that the log output is sent /usr/local. You will need to restart
any applications that are doing this if you use my method.

No rebooting necessary. I haven't tested it though! It may make you into a
disco dancing machine, or an alien might abduct you! (say hello to
green-belly from me)

Quote:> No rebooting necessary. I haven't tested it though! It may make you into a
> disco dancing machine, or an alien might abduct you! (say hello to
> green-belly from me)

I guess I will eventually have to do a reboot just to make sure the
adjustments to fstab have worked properly, but because I still have my
old /usr partition, if it turns into a disco-dancing machine and I get a
belly full of lead I can always login as root remount the old /usr
partition and be back where I started.

I love Linux.

--
Help! Windows has fallen and it can't get up!

If the order is:

/
/shared
/usr

everything would work fine.... But what would happen if things were changed
to:

/
/usr
/shared?

It would seem to me that since shared is a existing directory on the "/
(root) directory, /usr would (using to the mount -o bind /shared /usr
method) mount the /shared that is on the "/ (root)" partition and not to
the /shared partition. Sorry if this sounds crazy but it is the first time
I tried to think it trough... Could someone let me know if I'm on the right
track?

Quote:> *copy* the /usr to
> /shared (I use tar to save file ownerships...).

--

Ian - looking through a glass onion

But what if some new admin got things out of order? After all, new admins
don't always don't know all the "shouldn't happen(TM)". /usr can not be
mounted before / because the system can't find the /usr mount point without
/ being mounted. There is a good reason that / is mounted before /usr.

What I am asking is in your example:

Would mounting in this order:

/
/shared
/usr

give the same result as mounting in this order?

/
/usr
/shared

I know you think it shouldn't happen but I think it is important to discuss
WHY it should not happen. Unless a newbee understands WHY things sould and
should not happen, "should not happens" WILL happen. I have seen a new
admin try to mount /usr first! He had a habit of making changes by
commenting out a line then adding the new line at the bottom of the *file*
with comments like:

#
# added option <x> <date> <admin>
#

< new mount point line >

In the*case:
/usr has the same stuff in it as the /shared partition
In the second case:
/usr has the same stuff in it as the directory /shared on the / partition

You don't have to bind-mount different partitions, you can bind-mount
different directories. (which can be quite usefull when setting up a
chrooted ftp server)

    Ryan> Thanks guys, Ive got it all shifted over, remounted /shared
    Ryan> as /usr and everything seems to be going fine so far and no
    Ryan> rebooting :-).

Wow!  I'm too late to reply.

But in case you'd be doing simlar things again:

1) Rebooting is not really necessary.
2) You SHOULD go into single use mode first: telinit s
   Why?  Because many background processes may be accessing /usr.  If
   you move the files away, those process may get confused.  More
   severely, if some processes are modifying /usr, then you cannot
   be sure that you've got a clean an consistent _snapshot_ of the
   whole /usr into the new partition!
3) After entering single user mode, type "ps" to check if any
   unncessary daemons are still running.  Kill them if necessary.
   (Some programs may still be accessing /usr, making it impossible to
    "umount /usr".)
4) Unmount BOTH partitions from their default mount points, just
   as a last resort to make sure no programs are still accessing them.
5) mount both partitions to temporary mount points (e.g. something
   as impossible to clash as "/tmp/blah1", "/tmp/blah2"  :P).
6) transfer the files.  Use 'tar', 'cp -aiR' or 'mv'.  Check what
   options you need to do a recursive copying  that still
   preserves all file attributes (permission, owner/group setting).
8) umount the file systems.
9) mount the file systems at their new mount points.  Use ls, find or
   whatever to check if you've got the correct files in the correct
   places.
10) modify /etc/fstab to make the change permanent.
11) Go back to multi-user mode: telinit 5 (or 3 if you're not booting
    into X directly).

Note that moving the root partition  is another story.  If you want to
do that,  you'd better boot  up a floppy-only  Linux system and  do it
under it.  There is no _simple_ way  to do (4), (5) and (9) above on a
running system.   Without these  steps, you can't  be sure you  have a
consistent  snapshot.   There  is  a mechanism  like  'initrd'  called
pivoting for doing it.  But it doesn't worth the trouble.

Exercise: why  is there a /bin  and also a  /usr/bin?  Which utilities
should be in /bin and which should be in /usr/bin?

    Ryan> I guess I will eventually have to do a reboot just to make
    Ryan> sure the adjustments to fstab have worked properly,

Not necessary.  Just  unmount those 2 partitions, and  the do a "mount
/mountpoint".  Then, check if they have been mounted correctly.

    Ryan> but because I still have my old /usr partition, if it turns
    Ryan> into a disco-dancing machine and I get a belly full of lead
    Ryan> I can always login as root remount the old /usr partition
    Ryan> and be back where I started.

Yeah!  That's the safest way to try things out: make sure you can roll
back easily.

--

Home page: http://www.informatik.uni-freiburg.de/~danlee