Indexing large table of coordinates with GiST

Hi, I'm trying to create an index on coordinates (geography type) over a
large table (4.5 billion records) using GiST...

CREATE INDEX nodes_geom_idx ON nodes USING gist (geom);

The command ran for 5 days until my computer stops because a power outage!
Before restarting the index creation, I am asking the community if there are
ways to shorten the time it took the first time :-)

Any idea?

Daniel