Minimizing disk space

Howdy!

I'm currently in a MySQL -> PostgreSQL migration project (Go, go, go, ...
shall I cc: slashdot, too? ;-)

Part of this is in embedded context, where a (diskless) embedded computer
runs from flash. Since we don't want to stress the flash too much, the db
is actually loaded from a dump at boot and run off a ramdisk (and dumped
back to flash periodically.)

So all the nice database crash-safety that pg offers goes down the drain...

With this in mind: what can we tune to minimize diskspace (RAM-disk space)
usage? And, possibly, RAM usage as well (disk access is, after all, almost
as fast as RAM access in this scenario)

With our test dump, the db (after import) is ca. 300M on disk, ca. half in
WAL files (pg_xlog.) If I could mostly get rid of the WAL (keep it to a
bare minimum and run pg without fsync, something like that), the remaining
160 to 180M would be ok.

Next thing would be: are there tunables (compile time?) to minimize the
actual size of the rows?

Your input is valued, thanks in advance.

cheers
-- vbi

[... for the peanut gallery: we're migrating mostly because the cost of the
MySQL licenses is beginning to hurt us.]

--
A budget is just a method of worrying before you spend money, as well
as afterward.