Postgresql File System Level Backup Debian

In order to perform postgresql backup on debain, there are some modification on
http://www.postgresql.org/docs/9.1/interactive/backup-file.html

sudo service apache2 stop
sudo service postgresql stop

#%y%m%d_%H-%M
sudo tar -cvpjf /a/path/postgres-`date +%y%m%d`.tar.bz2 -C /var/lib/postgresql/9.1/main .

# Prevent parent directories from being tarred
#   -C, --directory DIR
#           change to directory DIR

# -p, --preserve-permissions, --same-permissions
#           extract information about file permissions (default for superuser)


sudo service postgresql start
sudo service apache2 start

# when extract
#sudo tar -xvjf postgres-xxxxxx.tar.bz2