Todd Vierling <tv@pobox.com> writes:
> On Mon, 31 Aug 1998, Todd Whitesel wrote:
> : > Using an MFS will eat a certain amount of swap space, etc.  Eat, not
> : > 'borrow.'  It's not a SunOS-style mfs that "borrows" space from swap,
> : 
> : I did note this in my original message.
> 
> Um, this is not quite true.  "Try it and see."  My mfs partitions are equal
> to the full size of my swap, and have been for ever since I've been using
> mfs (~a year now?).  Also, mfs doesn't even need swap space to exist in
> order to work.

sorry, i should have said "backing store" -- i.e. space out of the
"ram + swap" combination.  But it will eat that space, as you fill up
the file system.


Try to fill your MFS partitions, and have enough 'stuff' lying around
that your RAM is also full.  8-)

Then, after you've rebooted, fill them halfway, and note swap usage.
note that as you delete files, it doesn't decrease.


In an OS with a VM system that does working resource management, it
would actually be safe to use MFS (and your configuration would
probably be disallowed).  You'd use it, its potential space usage
would be accounted for, and the VM system would make sure (via
resource accounting and management, and refusing requests that it
cannot satisfy) that you never ran out of RAM+swap.  Of course, that
applies to more things than just MFS.  Issues like that are why people
who use NetBSD systems for interactive (potentially hostile) user
login boxes are ... brave, in my opinion.



cgd
-- 
Chris Demetriou - cgd@netbsd.org - http://www.netbsd.org/People/Pages/cgd.html
Disclaimer: Not speaking for NetBSD, just expressing my own opinion.
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