If you use pg_dump and get this error:
pg_dump: server version: <version>; pg_dump version: <version> pg_dump: aborting because of server version mismatch
Then do the following. Find the pg_dump that comes with the postgresql:
locate pg_dump
You may get something like this:
/usr/bin/pg_dump /usr/pgsql-<postgresql-version>/bin/pg_dump
Create a symlink to the server version:
sudo ln -s /usr/pgsql-<postgresql-version>/bin/pg_dump /usr/bin/pg_dump --force
Try pg_dump again.