swapon

[Dan Mick]

Just noticed the swapon(8), mkfile(8), and swapon(2) utils/syscalls in
SunOS 4.x (and, apparently, BSD 4.2 or 3).  

Would anyone care to post some practical experience with them?  

Is it a good idea, say, for example, to increase the swap space on my 
Sun-3/50 from the default swap partition?

If I have swaps on different physical disks, will I see a better performance
increase than on the same disk?

What sort of tradeoffs are there for number vs size on swap areas?

How about files vs. partitions?  Is there any reason to make partitions, or
is swapping on a mkfile'd file as good?

What sort of metric would one use for "good" for swap space, anyway, besides
not running out of it?