International Business Machines Corporation

Tseng-Hui Lin

Felipe Knop

Frank Bernhard Schmuck

Chun-Shi Chang

John Robert Hare

The determination of node and/or adapter liveness in a distributed network data processing system is carried out via one messaging protocol that can be assisted by a second messaging protocol which is significantly less susceptible to delay, especially memory blocking delays encountered by daemons running on other nodes. The switching of protocols is accompanied by controlled grace periods for needed responses. This messaging protocol flexibility is also adapted for use as a mechanism for controlling the deliberate activities of node addition (birth) and node deletion (death).

Computer program product using two different programs to determine state of a network node to eliminate message response delays in system processing

Method for adding new members to a group by sending a commit message with updated membership list to all nodes on the updated list

Method using two different programs to determine state of a network node to eliminate message response delays in system processing

In distributed multinode data processing systems, mechanisms are employed to insure that the nodes are properly informed about the liveness of the other nodes in node groups in the network. In particular, the present invention employs group membership indicia as part of a mechanism for detecting that a node and/or its adapter have failed and have been recently restarted. Having detected this situation, group membership inconsistencies which it can engender are avoided.

Method for detecting the quick restart of liveness daemons in a distributed multinode data processing system

In distributed multinode data processing systems, mechanisms are employed to insure that the nodes are continually informed about the liveness of the other nodes within node groups in the network and across networks. The method of the present invention employs the concept of node stability which it uses to provide indications of membership in a previous stable group as part of messages transmitted in a protocol for forming, maintaining and dissolving node groupings in such a way as to assure that all of the nodes in the group have a consistent indication of liveness status for all of the nodes within any given group of nodes.

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Poughkeepsie, NY, United States of America

Tseng-Hui Lin