Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!virtech!cpcahil
From: cpcahil@virtech.uucp (Conor P. Cahill)
Newsgroups: comp.unix.sysv386
Subject: Re: out of swap space??
Message-ID: <1991Apr24.123035.4193@virtech.uucp>
Date: 24 Apr 91 12:30:35 GMT
References: <1991Apr23.214037.16410@netcom.COM>
Organization: Virtual Technologies Inc.
Lines: 39

aed@netcom.COM (Andrew Davidson) writes:

>I am currently trying to port an application from a sun sparc station
>to SCO ODT UNIX. I seem to get some weird run time core dumps. I
>talked to the orginal authour of the code, and was told that this
>might because my system is running out of swap space?

If you don't get any messages on the console, I find it unlikely that 
the core dumps are being cause by running out of swap space.  Not 
impossible, just unlikely.

>HOW BIG SHOULD MY SWAP BE? I have 8megs of ram

My general rule of thumb is 2x your memory (or 16mb for your system).  Of
course, this depends upon the number and type of programs you inted 
to run and the real amount of memory you have.

>ARE THERE ANY TOOLS TO HELP ME MANAGE / MONITOR MY SWAP SPACE?

sar(1) will help you monitor it. (and will also tell you if you ran out
of swap space).

Do the following:

	sar -r 2 1000 > /tmp/sar.log 2>&1 &

Then run the application until it dies.

Review the sar output and if the freeswp had dropped to near zero, you
ran out of space.  If freemem dropped to near zero, you ran out of memory
and started swapping.

Note that it is unlikely that either one will actually get to zero, they
will just get real small.

-- 
Conor P. Cahill            (703)430-9247        Virtual Technologies, Inc.
uunet!virtech!cpcahil                           46030 Manekin Plaza, Suite 160
                                                Sterling, VA 22170