The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 20, 2001
Filed:
Oct. 21, 1997
Hossein Moiin, San Francisco, CA (US);
Angelo Pruscino, Mountain View, CA (US);
Sun Microsystems, Inc., Palo Alto, CA (US);
Abstract
Data integrity and availability is assured by preventing a node of a distributed, clustered system from accessing shared data in the case of a failure of the node or communication links with the node. The node is prevented from accessing the shared data in the presence of such a failure by ensuring that such a failure is detected in less time than a secondary node would allow user I/O activities to commence after reconfiguration. The prompt detection of failure is assured by periodically determining which configuration of the current cluster each node believes itself to be a member of Each node maintains a sequence number which identifies the current configuration of the cluster. Periodically, each node exchanges its sequence number with all other nodes of the cluster. If a particular node detects that it believes itself to be a member of a preceding configuration to that to which another node belongs, the node determines that the cluster has been reconfigured since the node last performed a reconfiguration. Therefore, the node must no longer be a member of the cluster. The node then refrains from accessing shared data. In addition, if a node suspects a failure in the cluster, the node broadcasts a reconfigure message to all other nodes of the cluster through a public network. Since the messages are sent through a public network, failure of the private communications links between the nodes does not prevent receipt of the reconfigure messages.