[comp.unix.ultrix] ps gives error

cathy@larry.sal.wisc.edu (Cathy Accettura) (07/12/89)

I am having problems tracking down a problem.  That
we appear to have every afternoon.  When I try to do
a ps I get not enough memory.  When I do a df I get
not enough core.  I don't see anything in crontab that
is causing the problem.  I can do a pstat but I don't 
know what I am looking for.

I need some tools to find out what the problem is.

I have a MicrovaxII runing Ultrix 3.0.

Cathy Accettura
University of Wisconsin-Madison
Space Astronomy Lab

grr@cbmvax.UUCP (George Robbins) (07/12/89)

In article <209@larry.sal.wisc.edu> cathy@larry.sal.wisc.edu (Cathy Accettura) writes:
> I am having problems tracking down a problem.  That
> we appear to have every afternoon.  When I try to do
> a ps I get not enough memory.  When I do a df I get
> not enough core.  I don't see anything in crontab that
> is causing the problem.  I can do a pstat but I don't 
> know what I am looking for.

Generic problems with ps and it's memory peeking friends are usually
caused by booting from a kernel other than 'vmunix', such as genvmunix
or a new kenel you've generated and not renamed.

Your description would seem to indicate other problems, however,
probably inadequate swap space.  'pstat -s' is the tool for examinging
this.  You want to look at the ratio of 'used' to 'free' - the other
numbers range from confusing to bogus (it's better in 3.0 than before).

You can be eating up swap space if you have users running memory hungry
applications like gnu-emacs or lisp, or if you have lots of not-so-big
stuff running.  Having logins enabled on 32 serial lines, 32 pseudo-ttys
and 32 lat pseudo terminals can chew up a surprizing amout of swap space.
You can look at the SZ field in a 'ps -aux' output to try to spot who
the big hawgs are.

If you need more swap space, you *need* more, otherwise all kinds of
'invisible' tasks like sendmail or uucp will be failing due to out
of memory problems and your life will become painful and confusing.

To add more swap space, you must first have somewhere to put it.
Hopefully, you have several disks and there are unused 'b' partitions
just waiting for such use.  You then need to config a kernel that
lists these partitions in "swap on" clauses in the config statment
in the config file and make entries for all *except* the first on
in fstab, so that the "swapon -a" command in your /etc/rc file will
activate the additiona area(s).

-- 
George Robbins - now working for,	uucp: {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@uunet.uu.net
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)

alan@shodha.dec.com ( Alan's Home for Wayward Notes File.) (07/12/89)

In article <209@larry.sal.wisc.edu>, cathy@larry.sal.wisc.edu (Cathy Accettura) writes:
> I am having problems tracking down a problem.  That
> we appear to have every afternoon.  When I try to do
> a ps I get not enough memory.  When I do a df I get
> not enough core.  I don't see anything in crontab that
> is causing the problem.  I can do a pstat but I don't 
> know what I am looking for.
> 
> I need some tools to find out what the problem is.

	You're probably running out of swap space.  If pstat
	will run use it look at how the swap space is being
	used.  The command is pstat -s:

		% psat -s 

		33440k swap configured
        		14056k used (3016k text, 0k smem)
        		19382k free, 4004k wasted, 2k missing
		avail: 33*512k 6*256k 2*128k 5*64k 2*32k 5*16k 230*1k

	The first line is the amount of space configured.  The 2nd
	line is how much is being used (and how much of that is text
	segments and shared memory).  The 3rd line is the amount that
	is available, wasted because of the swap space allocation
	algorithm and "missing".  "Missing" is whatever is left after
	configured - (used + free).  Missing should be small.

	The last line is how the available space is divided up.

	It is very easy for a large program to waste a lot of swap
	space.  You probably need to configure more.

> 
> Cathy Accettura
> University of Wisconsin-Madison
> Space Astronomy Lab

	Alan Rollow
	Digitial Equipment Corp.
	Colorado Springs CO.

collins@unmvax.unm.edu (Bill Collins) (07/13/89)

In article <209@larry.sal.wisc.edu> cathy@larry.sal.wisc.edu (Cathy Accettura) writes:
> I am having problems tracking down a problem.  That
> we appear to have every afternoon.  When I try to do
>  ... [can't allocate memory for commands]

If you are running DECwidnows perhaps you should look for masive leaks in
the X server and clients.  As you use DECwindows, memory leaks and they just
soak up memory.  If it is, DEC should have taken care of most if not all of
the memory leaks in the comming release.

> a ps I get not enough memory.  When I do a df I get
Ps allocates a bit of memory to show processes.  Its one of the first to fail.

> not enough core.  I don't see anything in crontab that
Yes, df does some allocation too.  Its not cron.

> is causing the problem.  I can do a pstat but I don't 
> know what I am looking for.
Look for low virtual memory, processes crashing due to memory shortages, etc.

Most people who run it around here just reboot.  Some go to X11 from MIT.
Some cut usage down on DECwindow displays.  Some just suffer and will wait
until the next version gets here.

Have fun,
	Bill
-- 
			collins@unmvax.unm.edu
			gatech!unmvax!collins

sps@magoo.mcnc.org (Stephen P. Schaefer) (07/13/89)

Just today we saw this problem (ps & df complaining about memory) on a
few Vaxstation 2000's with about 16 megabytes of virtual memory
running Ultrix 3.0, no DecWindows.  You are probably running out of
virtual memory.  For our variety of processes, the biggest culprit was
an X server with SZ > 6 meg of virtual space, according to ps -aux
(when we could run ps).  I don't understand the server's memory use.
We have never observed the server grow smaller, regardless of numbers
or size of clients.  Workstations with similar (of course, not
identical) job mixes, numbers of clients, window managers and up time
will have X servers using only 2 meg.

I killed the X server and it restarted using a mere 1 1/2 meg; I am
now checking it every time something infrequent happens (window
glitches and assorted whimsy); it's grown less than 100k in the last
four hours.

--
	Stephen P. Schaefer, Postmaster	MCNC
	sps@mcnc.org			P.O. Box 12889
	...!mcnc!sps			RTP, NC 27709

graham@fuel.dec.com (kris graham) (07/13/89)

> 
> ...  When I try to doa ps I get not enough memory.....   
   
 
Could be a swap space problem.  Up your swap size and tell
us what happens.


Christopher Graham          
Digital Equipment Corp            
Ultrix Resource Center                            
2 Penn Plaza      
New York City