Path: utzoo!censor!geac!torsqnt!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!snorkelwacker!mit-eddie!mit-amt!wilson
From: wilson@mit-amt.MEDIA.MIT.EDU (Wilson Chan)
Newsgroups: comp.sys.next
Subject: Re: How do I shrink the swapfile (easily...)
Message-ID: <1730@mit-amt.MEDIA.MIT.EDU>
Date: 1 Mar 90 14:32:51 GMT
References: <2558@cs-spool.calgary.UUCP>
Reply-To: wilson@media-lab.media.mit.edu (Wilson Chan)
Organization: MIT Media Lab, Cambridge MA
Lines: 26

In article <2558@cs-spool.calgary.UUCP> schock@cpsc.ucalgary.ca (Craig Schock) writes:

[stuff deleted]

>	What I want to know is ... Is there an EASIER way to bring
>the swapfile back down to size?  Since we are on a 330 Meg HD with only 
>58 Megs free a jump in the size of the swapfile from 21 megs to 41 megs
>can cause some problems.  Most VM systems I've worked with don't have a
>"growing" swapfile so this little incident came as a little of a shock.
> 
>Thanks in advance
>
>========================================================================
>Craig Schock                               schock@cpsc.UCalgary.CA
>University of Calgary  (More reliable ->)  schock@flip.cpsc.UCalgary.CA
>========================================================================

The file, /etc/swaptab, controls the swapfile size.  Here's the original file:

/private/vm/swapfile	lowat=20971520	#  20 Meg low water mark

The OS will "attempt" to shrink the swapfile down to lowat.  Similarly, you
can add a hiwat entry which tells the OS not to grow infinitely big.  I think 
the keyword here is "attempt".  My swapfile stays at 20Meg even when I set the
lowat to 16Meg and only a Terminal is running.  

--wilson