@Xiang, when you comment a parameter, a default value is applied. For connection it is sqlite:////savanna/openstack/common/db/$sqlite_db (the one you can see in the sample config file)

The change you see is non intentional. Both current configuration and the old one will work fine. It is just a location for storing sqlite database.

The correct configuration is: connection=sqlite:////var/lib/savanna/savanna-server.db

openstack-savanna-0.3-2.el6.noarch should have the correct location. Check for a /etc/savanna/savanna.conf.rpmsave or .rpmnew file.

It will still run w/o the connection line, but your savanna-server.db may be written to /tmp, which may be wiped on system reboot.

Since you are using the RDO Havana RPMs, the correct location is /var/lib/savanna/savanna-server.db (happens to be ~savanna/savanna-server.db).