Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!virtech!cpcahil
From: cpcahil@virtech.UUCP (Conor P. Cahill)
Newsgroups: comp.unix.i386
Subject: Re: How do I measure the 386/ix paging rate?
Summary: Use sar(1)
Message-ID: <1187@virtech.UUCP>
Date: 21 Sep 89 12:37:14 GMT
References: <1989Sep20.141733.5037@esegue.segue.boston.ma.us>
Distribution: na
Organization: Virtual Technologies Inc
Lines: 30

In article <1989Sep20.141733.5037@esegue.segue.boston.ma.us>, johnl@esegue.segue.boston.ma.us (John R. Levine) writes:
> My 386/ix box running 2.0.2 is doing a lot of disk I/O these days, and I
> think it is paging too much.  Before I shell out 500 bucks to get more
> memory, it would be nice to know for sure.  Is there any way to find out
> what the paging rate actually is?

You can use the sar(1) program which will give you a system activity report.
You can use different options to sar to display the paging/swapping, syscalls,
memory....

> For that matter, what sort of paging algorithm does it use?  Performance
> seems to have gotten worse since I installed NFS.  I have the usual bunch of
> nfs daemon processes, but since there are no active clients I'd hope they'd
> get swapped out.  Or do I hope too much?

I don't know what algorithm is used, but I *think* that most paging systems
will page out sections of programs before they decide to swap out a whole 
program.

There are a couple of configuration parameters that you can use that effect
the paging/swapping.  These include the minimum amount of free space 
to maintain (in %) and other such stuff.   I have never modified these settings
in my machine so I can't give you any suggestions.  The system administrators
guide does have a pretty good discussion on performance tuning.

-- 
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| Conor P. Cahill     uunet!virtech!cpcahil      	703-430-9247	!
| Virtual Technologies Inc.,    P. O. Box 876,   Sterling, VA 22170     |
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