nova-manage user list
2012-01-03 20:42:39,539 DEBUG nova.utils [79b4894e-a55b-4d09-9a1c-20041dea78f5 None None] backend <module 'nova.db.sqlalchemy.api' from '/usr/lib/pymodules/python2.6/nova/db/sqlalchemy/api.pyc'> from (pid=12391) __get_backend /usr/lib/pymodules/python2.6/nova/utils.py:525