*BSD News Article 20230


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Newsgroups: comp.os.386bsd.questions
Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!agate!howland.reston.ans.net!noc.near.net!Lotus.com!Temp.lotus.com!temp!jkh
From: jkh@thrush.lotus.com (Jordan K Hubbard - he's back again)
Subject: Re: swap space, X server for syscons-0.2
In-Reply-To: wongm@latcs1.lat.oz.au's message of Wed, 25 Aug 1993 14:46:57 GMT
Message-ID: <JKH.93Aug30183524@thrush.lotus.com>
Sender: news@lotus.com
Nntp-Posting-Host: 130.103.186.134
Organization: Lotus Ireland
References: <CCBL2A.IyH@latcs1.lat.oz.au>
Date: Mon, 30 Aug 1993 17:35:24 GMT
Lines: 53

>And I got swapinfo to check on the use of my swap partition. And as it
>reveals, 5 MB is definitely too small. But there is one thing I do not quite
>understand the way 386bsd does virtual memory  management. I have tried
>running some applications (like xfig, ghostview, etc) and did swapinfo
>before, during and 

Yup, 5Mb is WAAAY too small..  You definately need to reconfigure.  As
to why swapinfo still shows pages as "used" when the programs running
them are obviously no longer running, I am not exactly sure, not being
a VM expert either, but I think it is because the swap space is not
reclaimed until you actually need it again.  I would think this would
speed the reactivation of images previously run but not yet "flushed"
from the swap area (or do you need to set the sticky bit explicitly to
get this behaviour?).  Just a theory, anyway - I really should RTFS
(you might too, that's what it's there for).

>that has bug fix for line drawing function. I wonder does there exis a
>version for syscons-0.2 as well ? I am running syscons-0.2 and feel
>that its performance

I am also running syscons 0.2 - NO changes are needed, as syscons
emulates pccons as far as X is concerned.  Oh yes, I did have to make
one change to syscons to get the bell working again, but that's been
folded into syscons now and should be available from the author soon.
Alternatively, you can grab it out of the FreeBSD distribution since
I've updated it there.

>  One last question, I remember reading some general guidelines/formula for
>allocate swap space from the book "Unix Administration Handbook", but can't

Easy rule of thumb: swap space = (main_mem * 2) * fudge

Assuming a fudge of 1, if you have 8MB of main memory then 16MB of
swap is good.  Bump fudge up to 1.4 or so if you have less than 16MB
of memory and you're running KCL, or lots and lots of X clients!
If you've got >16MB of memory, I'd say leave fudge at 1.

>wonder if someone can let me know ? Also, I plan to disklabel my new disk
>in such a way that I am leaving some "hole" between parition b and other 
>paritions to leave some room for grow for the new additional swap partition,
>is that feasible ? Has anyone done it before ? How about if I use the extra

Sure, that'd work.  To augment an existing fs the hole will have to be
tail-adjacent to the existing one and you'll also have to re-make the
fs to use it, of course.  Then again, making filesystems span
partitions is more than a little evil and I'd recommend against it
(collapse the partitions back into one before doing it) - it will
certainly work, but it will confuse the hell out of people and leave
you in a very uncertain state if you ever accidently delete the
partition, or make it active from DOS.  Ugh.  Yeah, definately, don't
do it!  Use it for swap.

					Jordan