I think it would be simpler to support the fairly common syntax of host:port

hibernate.ogm.datastore.host ip1:123, ip2:456

This is less fragile that the hosts + ports in two different properties.

Speaking of, I think it would be even better if we offer a hibernate.ogm.datastore.url mongodb://ip1:123,ip2:456.
This avoids the misname "host", is more flexible and I think will be useful to other datastores.