pg_dump with the
-Fc flag will create a dump of the given
database in a custom format. The output of this command can be redirected
into a file (the
.dump extension is a standard convention):
pg_dump -Fc my_database > my_database.dump
Using the custom format option provides a couple benefits. The output is significantly compressed in comparison to a generic SQL dump. The dump and restoration is more flexible. Lastly, the dump can be performed in parallel if your machine has multiple cores to work with. Likewise, the restoration can be done in parallel with multiple jobs.
for more details.