James Cloos <cloos(at)jhcloos(dot)com> writes:
> Right after the restore the db took up less than ten percent as much
> space as the backup. (For the backup I stopped pg and used rsync on
> the /var/lib/postgresql/data directory.)
> Why was the db using that extra five plus gigs?
Smells like a hadn't-been-vacuuming-often-enough problem.
Please note that vacuum-full-once-in-a-long-while is *not* a substitute
for frequent-plain-vacuum, because VACUUM FULL isn't good at reducing
index space usage --- in fact it usually makes it worse. Your numbers
didn't separate table vs index bloat, but I'm suspicious that a lot of
your problem was the latter.
regards, tom lane