Using an SSD as swap?

[jack-rp9/bkPP+cDYtjvyW6yDsg at public.gmane.org (Jack Coats)]

If you can find a solid state drive that is NOT flash based and has great I/O
ability, I would suggest putting swap on it, if you swap a lot.  Prior
to that adding
more main memory is probably a better idea.

<war story>
In the days when mainframes wandered the earth and 16M was considered a lot
of memory, we paged (prior to swapping being the norm) to 'head per
track' disks,
then moved the paging to drum (it spun faster, otherwise same technology) and
really got a speed boost by going to solid state disk.  The head seek time, and
rotational latency can be a killer if you MUST swap/page.
</war story>

Flash is better now, but it still retains a limited life of read/write
cycles.  So using
any flash based for 'regular write' file systems is asking for the
file systems to fail
before they must.

The new implementations that let you 'run from a flash drive' (sd
card, USB dongle, whatever)
suggest you have enough memory, so they can cache just about
everything to memory,
and they only write to the flash drive when they MUST.  This
significantly helps in
lengthening the life of the flash in these devices.  The file systems
on these devices,
if I remember correctly, also varies where it writes, so the 'wearing
out' due to writing
to an area is distributed over most of the card and not just in one
place.  Another good
technique to get more life from the 'limited number of write' media.

I hope this helps a little.