> > What is the pro and con of having a file system that large on NetBSD
> > or on a unix box, in general?   I was of the impression that if the
> > file system sizes grew there was a slowdown in file system speed due
> > to the time to traverse heads across the larger file systems.  Is that
> > correct, or am I misunderstanding how it works?
> 
> It really depends on your application. ;-)
> 
> For myself, i mostly choose this sizes accordingly to my backup.

OK, I would accept that.  Are there any other specific reasons to
size file systems down lower than 17gigs or the remainder of the
disk after root and swap and maybe var?  I am thinking of things like
optimizing access speed, and that kind of thing.  Practically for most
of us it probably does not make much real difference.   But, IFF I were
fine tuning a machine for speed, what should I think about in terms
of file system sizes?  Or, is it practically unimportant these days?
 
.....

> Nope. Your swap is virtual memory. For example, if you have 128MByte RAM,
> and 384MByte Swap, you could compute data sets, which are up to 512 Mbyte in
> size. (without thinking about the OS, drivers, ...)
> It's an stupid example, but i hope it tells something.

OK, it does.  Now, that begs the question..... what occasions are there
to require such large virtual memory usages?  Your large data set is one
good example.   But, for most NetBSD users, what others might one run
across in the general use of a machine?  Few folks are grinding 512mb
data sets on the average home Joe's machine.  What ``memory'' would running
a small medium or large hit rate web server need?    What would be
required for 2 users vs 10 users vs 100 users vs 1000 users, on average?
What actually gets used when compiling the whole system from scratch?
That is the kind of information I am trying to get a reasonable sense for,
so that when I set down at a new machine and set it up, I have a good
understanding of why I need to set it up this way or that way.   Some
of it is a black art and hocus pocus, but there is reasoning behind
it, in most instances.   And, for me, I wanna know why?

> > If you have lots of memory, you did not need so much swap.
> 
> Ok, take the answer this way:
> If you have more memory in your system, that you EVER need, you don't need a
> swap ;-)

Precisely.   If you had tons of memory, then a tiny swap partition suitable
for minor maintenance or upgrade needs might be all that would be required.
That would not be the classical 2 x ram sized swap system, in that case.
For example, my DS5000/200 with 96mb ram, probably will not hit its ram
limit under almost all my usage conditions.  Thus a small swap of 32mb is
probably sufficient.   That would be enough to dd images and the like to,
if needed, or enough to keep the machine from dying if I did one time or
two run full up to 96mb.
 
.....

> For myself, on a usual system, at least the amount of RAM. In your case, 64
> or 128 MByte. It doesn't hurt anyway, on a 17 GByte disk.

True, but it does hurt on a pair of 300mb drives that are currently on
the machine.....(:+{{.  (I am rectifying that situation shortly though.)
 
> But it hurts, if you run out of Memory ...

For the sake of more discussion, what conditions would run out of 96mb
of ram and say a 32mb swap partition, barring the extremely large database
example you mentioned?  I would have a hard time thinking of anything
that I have done on smaller unix machines that would press that limit.
My usual machines are 16-32mb ram, 32-64mb swap machines or smaller
(like a 4 meg ram AIX box with 6 megs swap that has been my ftp server
for 12 years... never yet run out of memory on compiles, up/downloads,
usage by up to 10 users at one time, etc.).   I can't ever remember the
time that I have knowingly run out of memory or virtual memory on any
machine.  Thus, I am thinking the need for more than a minimum or maybe
a dump space (ram plus a few bytes) is often wasted.   But, now that I
am beginning to work with some larger ram machines, I need to appreciate
and understand the what and why for their ram/swap usages and needs.

> > Thanks.... lots of questions and the ol' propeller beanie is spinning
> > wildly, today.....(:+\\...
> 
> Why not, is so quiet here ;-)

Well, it sure helps this ol' greybeard, propeller-beanie-headed feller!

Thanks!

Bob