[comp.unix.aix] User Directories

somsky@brl.mil (William R. Somsky) (04/26/91)

With the '/usr' partition sucking up almost the entire hard-drive on
installation, is there really any good reason for putting users on a
seperate '/u' partiton?  I've heard suggestions of soft-linking '/u' or
'/u/<username>' to directories on '/usr', but can anyone think of a
reason that I wouldn't want to just put all users DIRECTLY on the
'/usr' partition, say, in something like '/usr/u', and modify
'/etc/passwd' to match?  (Is it perhaps that SMIT insists on putting
users in'/u'?)  

Any comments on this matter?

							W R Somsky

eravin@panix.uucp (Ed Ravin) (04/27/91)

In article <709@aos.brl.mil> somsky@brl.mil (William R. Somsky) writes:
>With the '/usr' partition sucking up almost the entire hard-drive on
>installation, is there really any good reason for putting users on a
>seperate '/u' partiton?

Plenty of them.  For starters, it's always nice to separate system
programs and vendor programs from what your users are doing.  I like being
able to re-install AIX (which wipes out the / and /usr filesystems)
without having any of my user's files affected.  And system administration
in general is less complex when your users and your system programs are
on different filesystems -- for example, suppose a user fills up his or her
directory with large files, eventually flooding the filesystem.  If the
user's directory was in /usr, then uucp spooling and a number of other
daemons would grind to a halt.  If the users were all segregated in /u,
then that couldn't happen.
-- 
Ed Ravin            | I'm sorry, sir, but POSTAL REGULATIONS don't allow
cmcl2!panix!eravin  | PLASTIC tape over PAPER tape and NYLON cord on an
philabs!trintex!elr | 86 inch girth to LITHUANIA...
+1 914 993 4737     |

wangh@beasley.CS.ORST.EDU (Haiyan Wang) (04/27/91)

In article <709@aos.brl.mil> somsky@brl.mil (William R. Somsky) writes:
>With the '/usr' partition sucking up almost the entire hard-drive on
>installation, is there really any good reason for putting users on a
>seperate '/u' partiton?  I've heard suggestions of soft-linking '/u' or
>'/u/<username>' to directories on '/usr', but can anyone think of a
>reason that I wouldn't want to just put all users DIRECTLY on the
>'/usr' partition, say, in something like '/usr/u', and modify
>'/etc/passwd' to match?  (Is it perhaps that SMIT insists on putting
>users in'/u'?)  
>
>Any comments on this matter?
>
>							W R Somsky

Well. /usr contains a lot of system stuff and it need room for grow. At
least need some space for all sort of spool space. If you put the user home
directory inside /usr, then there will be some good chance /usr get filled
up by user files and you don't have any spool space. Well, it will be
another story if you put /usr/spool in a partition of its own. 

By the way, I never understood why the /usr partition is sooooooooo big.
I asked the so called 'SE' to make /usr just big enough to hold the system
stuff and we can always increase it later on. But the 'SE' seems never
understood my request at all. (Is it typical for IBM?). He made a 400M
/usr out of a 600M disk. Leave us with a ~60M /u and about 150M empty in
/usr. I was reall upset with this dummy SE. 

Guangliang He
ghe@physics.orst.edu

mike@bria.UUCP (Michael Stefanik) (04/28/91)

In an article, wangh@beasley.CS.ORST.EDU (Haiyan Wang) writes:
|Well. /usr contains a lot of system stuff and it need room for grow. At
|least need some space for all sort of spool space. If you put the user home
|directory inside /usr, then there will be some good chance /usr get filled
|up by user files and you don't have any spool space. Well, it will be
|another story if you put /usr/spool in a partition of its own. 

Acutally, the /usr filesystem does not need to be *that* large.  When
IBM ships us preloaded systems, the lpp's are in /usr, thus the reason
that it is so large.  I simply backup /usr, remove it, and recreate it
with crfs.

|By the way, I never understood why the /usr partition is sooooooooo big.
|I asked the so called 'SE' to make /usr just big enough to hold the system
|stuff and we can always increase it later on. But the 'SE' seems never
|understood my request at all. (Is it typical for IBM?). He made a 400M
|/usr out of a 600M disk. Leave us with a ~60M /u and about 150M empty in
|/usr. I was reall upset with this dummy SE. 

Again, simply backup, delete, and recreate the /usr filesystem; not including
the backup, it's 10 minutes worth of work.  Not worth complaining about, IMHO.
-- 
Michael Stefanik, MGI Inc, Los Angeles | Opinions stated are never realistic
Title of the week: Systems Engineer    | UUCP: ...!uunet!bria!mike
-------------------------------------------------------------------------------
If MS-DOS didn't exist, who would UNIX programmers have to make fun of?

mike@bria.UUCP (Michael Stefanik) (04/28/91)

In an article, somsky@brl.mil (William R. Somsky) writes:
|I've heard suggestions of soft-linking '/u' or
|'/u/<username>' to directories on '/usr', but can anyone think of a
|reason that I wouldn't want to just put all users DIRECTLY on the
|'/usr' partition, say, in something like '/usr/u', and modify
|'/etc/passwd' to match?  (Is it perhaps that SMIT insists on putting
|users in'/u'?)  

SMIT actually has nothing to do with the actual creation of the user
account; the real job is done by mkuser.  To change the filesystem
that the user accounts are created, edit /etc/security/mkuser.default
and change the "home" stanza.  You'll grok it when you see it.

-- 
Michael Stefanik, MGI Inc, Los Angeles | Opinions stated are never realistic
Title of the week: Systems Engineer    | UUCP: ...!uunet!bria!mike
-------------------------------------------------------------------------------
If MS-DOS didn't exist, who would UNIX programmers have to make fun of?

wangh@beasley.CS.ORST.EDU (Haiyan Wang) (04/29/91)

In article <223@bria.UUCP> uunet!bria!mike writes:
>
>Again, simply backup, delete, and recreate the /usr filesystem; not including
>the backup, it's 10 minutes worth of work.  Not worth complaining about, IMHO.

Don't you have to reload from tape? :-(. 
By the way, backup and reload are the major part of the whole work. They are
going to take at least 2 hours to finish. Of course, you can skip these two
steps and come up with a empty /usr. What a achievement!!!

I'm complainning because the SE could do the right thing at very beginning and
he did not. We are paying him $$$ for service. He's the one earning big $$$
by doing the job.

>-- 
>Michael Stefanik, MGI Inc, Los Angeles | Opinions stated are never realistic
>Title of the week: Systems Engineer    | UUCP: ...!uunet!bria!mike
>-------------------------------------------------------------------------------
>If MS-DOS didn't exist, who would UNIX programmers have to make fun of?

Guangliang He
ghe@physics.orst.edu

graeme@ccu1.aukuni.ac.nz (Graeme Moffat) (04/29/91)

mike@bria.UUCP (Michael Stefanik) writes:
>Again, simply backup, delete, and recreate the /usr filesystem; not including
>the backup, it's 10 minutes worth of work.  Not worth complaining about, IMHO.

 Michael, could you post the details of how to do this?  I've seen several
 others asking how, it must be a candidate for the FAQ. There's something I'm
 missing to umount /usr, even in maintenance mode.
Thanks
-- 
Graeme Moffat                g.moffat@aukuni.ac.nz \ Time wastes us all, 
Computer Aided Design Centre,  Fax: +64-9-366-0702 /  our bodies & our wits
School of Engineering,    Ph: +64-9-737-999 x8384 /  But we waste time,
University of Auckland, Private Bag, Auckland, NZ \   so time & we are quits

julie@levell.austin.ibm.com (Julie A. Levell) (04/29/91)

In article <709@aos.brl.mil> somsky@brl.mil (William R. Somsky) writes:
>With the '/usr' partition sucking up almost the entire hard-drive on
>installation, is there really any good reason for putting users on a
>seperate '/u' partiton?  I've heard suggestions of soft-linking '/u' or
>'/u/<username>' to directories on '/usr', but can anyone think of a
>reason that I wouldn't want to just put all users DIRECTLY on the
>'/usr' partition, say, in something like '/usr/u', and modify
>'/etc/passwd' to match?  (Is it perhaps that SMIT insists on putting
>users in'/u'?)  
>
>Any comments on this matter?

No, smit (or mkuser) will let you put home directories where ever you
like.  You should also check out /etc/security/mkuser.sys
which creates the user's home directories, etc.

Sounds like a good idea to me.

>
>							W R Somsky


-- 
*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
Julie A. Levell  IBM  Austin, Texas      Internet: julie@aixwiz.austin.ibm.com
IBMNET: JULIEL at AUSVMQ 4C-29/994       SpeakNet:  823-5178 (Tie 793-5178)
"Let's use the ODM Interface"  Commander William Riker  STTNG  "The Nth Degree"

mike@bria.UUCP (Michael Stefanik) (05/01/91)

In an article, wangh@beasley.CS.ORST.EDU (Haiyan Wang) writes:
>Don't you have to reload from tape? :-(. 
>By the way, backup and reload are the major part of the whole work. They are
>going to take at least 2 hours to finish. Of course, you can skip these two
>steps and come up with a empty /usr. What a achievement!!!

Well, I didn't really count the backup and restore because you can always
be doing something else useful ... for example, I always return to my
true vocation, and fire up an intense game of NetHack. :-)

BTW, I doubt very much that these IBM SE's are earning the "big bucks".
We had a guy migrate from our company to IBM, and he took a salary *decrease*
(why, in God's name, I have no idea -- guess he wanted those big blue letters
on his resume) to do it.  Methinks the idea that working for IBM gets you
the pot 'o gold on the other side of the rainbow is but a myth.

My advice when struggling against a problem with IBM software or hardware:

	1. Take a deep breath.  Hold it.  Think about your mother.  Exhale.
	2. Remind yourself that life is wonderful and worrying gets you nowhere.
	3. Read a chapter from "I'm OK, You're OK"

-- 
Michael Stefanik, MGI Inc, Los Angeles | Opinions stated are never realistic
Title of the week: Systems Engineer    | UUCP: ...!uunet!bria!mike
-------------------------------------------------------------------------------
If MS-DOS didn't exist, who would UNIX programmers have to make fun of?

mike@bria.UUCP (Michael Stefanik) (05/02/91)

In an article, graeme@ccu1.aukuni.ac.nz (Graeme Moffat) writes:
> Michael, could you post the details of how to do this?  I've seen several
> others asking how, it must be a candidate for the FAQ. There's something I'm
> missing to umount /usr, even in maintenance mode.

To "shrink" the /usr filesystem back down to an optimum size,
which is about 140,000 blocks (70M), take the following steps:

	1. go into maintenance mode using the "/etc/shutdown -Fm"
	   command; wait until the single user message is given
	   by INIT.

	2. backup all of the files in /usr, using the command:

		# find ./usr -print | backup -iqvf /dev/rmt0

	3. unmount the /usr filesystem using the "/etc/umount /usr"
	   command

	   IF THE UNMOUNT FAILS, THEN IT'S BECAUSE YOU'RE USING THE
	   KORN OR BOURNE SHELL.

	   Switch to the C shell using the command "exec /bin/csh"

	4. remove the /usr filesystem using the command "rmfs /usr";
	   the filesystem MUST be unmounted in order to do this.
	   the "dspmsg" command will not be found; ignore this error.
	   edit /etc/filesystems, removing the /usr stanzas

	5. create a new /usr filesystem using the command:

		# crfs -v jfs -grootvg -a size=140000 -m/usr -Ayes -prw

	6. mount the new /usr filesystem using the "/etc/mount /usr"
	   command; check it using the "df -v" command.

	7. restore the file using "restore -xqvf /dev/rmt0"

	8. Sync and reboot the system; you now have a smaller /usr
	   filesystem

This should be about it.  Works for me, but try at your own risk.  Your
mileage may differ.

-- 
Michael Stefanik, MGI Inc, Los Angeles | Opinions stated are never realistic
Title of the week: Systems Engineer    | UUCP: ...!uunet!bria!mike
-------------------------------------------------------------------------------
If MS-DOS didn't exist, who would UNIX programmers have to make fun of?

buchholz@ese3.ogi.edu (Don Buchholz) (05/09/91)

In article <709@aos.brl.mil> somsky@brl.mil (William R. Somsky) writes:
>With the '/usr' partition sucking up almost the entire hard-drive on
>installation, is there really any good reason for putting users on a
>seperate '/u' partiton?  I've heard suggestions of soft-linking '/u' or
>'/u/<username>' to directories on '/usr', but can anyone think of a
>reason that I wouldn't want to just put all users DIRECTLY on the
>'/usr' partition, say, in something like '/usr/u', and modify
>'/etc/passwd' to match?  (Is it perhaps that SMIT insists on putting
>users in'/u'?)  
>
>Any comments on this matter?

If, for whatever reason, you should have to reinstall the AIX OS,
then according to page 2 of the Installation Guide, the following
directories will be erased and recreated: /bin, /dev, /etc, /lib, /info,
/tmp, and /usr.  So it might save a bit of restoration time if the 
users were actually in /u.  

I've also heard rumors (as yet unsubstantiated) that a major OS 
upgrade would thrash these same directories.  I suppose something
like a move to AIX 4.x would do it.  [At the rate IBM is sending out
upgrades that'll probably be '92 :-)].

Don Buchholz                   
Oregon Graduate Institute     
buchholz@ese3.ese.ogi.edu