Fun fact: pg_dump -Fc on a 110+GiB DB (pleroma's DB), different levels of compression:
0: probably same size as database, didn't stick around to find out, it did pass 20GiB mark VERY quickly. 1: ~15GiB, ~20min 2: ~14GiB, ~20min 3: didn't test 4: ~12GiB, ~24min 5: ~11GiB, ~26min 6: ~11GiB, ~30min (default?) ... 9: ~11GiB, ~1hour