Patent ID: 7739235

Claim:
A method for dynamically managing persistent membership of a coordination group in a distributed environment, the coordination group including a number of sites included in a persistent membership, with one or more of the sites including a database and a registrar, the method comprising: receiving, by a registrar of a first site that is a member of the persistent membership, a Membership Request from an entrant seeking to become a member of the persistent membership; modifying, by the registrar of the first site, the persistent membership for the entrant; acquiring, by a fault tolerant distributed lock manager associated with the registrar of the first site, a distributed lock on the coordination group and entrant name; responsive to the register receiving the membership request, examining, by the registrar of the first site, the persistent membership to determine if a name of the entrant is already in use; responsive to a determination that the name of the entrant is not in use: disconnecting the registrar of the first site from the coordination group so that the registrar of the first site, while initializing a database for the entrant, does not apply updates to or from a database in other sites of the coordination group while the other sites are able to update at least one database in the coordination group; initializing the database for the entrant; and reconnecting, by the registrar of the first site, to the coordination group after initialization of the entrant database; responsive to a determination that the name of the entrant is in use: refusing, by the registrar of the first site, to proceed with initializing the database; aborting, by the fault tolerant distributed lock manager, any transactions in process; releasing, by the fault tolerant distributed lock manager, any locks held by the registrar of the first site; and disconnecting, by the registrar of the first site, from a group communication system providing an extended virtual synchrony service to the coordination group thereby allowing the registrar of the first site to provide a consistent snapshot to the entrant.