International Business Machines Corporation

Tushar Deepak Chandra

John Arthur Pershing, Jr

Peter Richard Badovinatz

Orvalle Theodore Kirby

Ajei Sarat Gopal

Larry Bert Brenner

Marc Adam Kaplan

Marion Lee Blount

Daniel Charles Sturman

Robert Evan Strom

John Joseph Turek

Dennis Duane Jurgensen

John Joseph Edward Turek

Liana Liyow Fong

Vijay Krishnarao Naik

Michael James Ward

Guruduth Somasekhara Banavar

William Francis Jerome

Kevan Lee Miller

Srirama Mandyam Krishnakumar

Ching-Yun Chao

Roger E Hough

Amal Ahmed Shaheen

Mark C Astley

Sameh Afif Fakhouri

Daniel Ming-Te Hsieh

Rodolfo Augusto Mancisidor-Landa

Javashree Ramanathan

Orvalle Theordore Kirby

Ahmed-Sameh Afif Fakhouri

Jr John Arthur Pershing

A technique for reliably multicasting a message within a router network is provided. At least one special router in the network has associated persistent storage for logging a message being routed to one or more clients. When a message is received at this logger node, the logger places the message in persistent storage and sends a logging acknowledgment back to those routers to which the message was originally routed, as well as back towards the source of the message. The logger acknowledgment includes the message id, the logger id, and a logging number. When the logger acknowledgment is received by a router, it looks up the routing information from the original message, and sends the acknowledgment to those neighboring routers to which the original message was sent, excluding the link from which the logger acknowledgment was received. If the original message corresponding to the logger acknowledgment was buffered at this router waiting to be delivered, the message is then delivered to its client nodes. Processes for recovering from node or link failure within the router network, and for at most once delivery of messages, at least once delivery of messages, and exactly once delivery of messages are also provided.

Message logging for reliable multicasting across a routing network

Program product for an application programming interface that unifies a plurality of mechanisms into a single framework. The interface includes a mechanism for communicating between members of a process group of related processes, and a mechanism for synchronizing the related processes of the process group. Additionally, the application programming interface may include mechanisms for managing membership of the process group or a processor group of processors, and/or a mechanism for controlling a group state value for the process group.

Program product for an application programming interface unifying multiple mechanisms

A scalable merge technique for information retrieval across a distributed network is provided, as well as a fault tolerant technique for communicating information across the distributed network. The merge technique includes multicasting a query request across a spanning tree of the distributed network from a root node to multiple clients of the tree, and receiving back at the root node, a merged response produced from responses from at least some of the clients of the spanning tree. The fault tolerant technique for communicating information across the distributed network includes assigning a unique identifier to each query request, automatically reconfiguring the network upon detection of a failure of a node of the network, and retransmitting the query request and/or any responses thereto within the reconfigured network.

Scalable merge technique for information retrieval across a distributed network

The number of instances of an application running in a computing environment are controlled by monitoring the current load on the application, and altering the current number of instances of the application based on results of the monitoring. The load may be monitored by monitoring the current number of instances of the application running in the computing environment. Where a maximum, minimum and/or initial number on startup, of instances of the application are specified, the altering is done based on comparing the current number to one or more of the specified numbers of instances.

Controlling a number of instances of an application running in a computing environment

A technique for reliably multicasting a message within a router network in a sequenced order with other messages is provided. At least one special router in the network has associated persistent storage for sequencing a message being routed to one or more clients. When a message is received at this sequencer node, the sequencer places a sequence number for the message in persistent storage and sends a sequencing acknowledgment back to those routers to which the message was originally routed, as well as back towards the source of the message. The sequencer acknowledgment includes the message id, and the sequencing number. When the sequencer acknowledgment is received by a router, it looks up the routing information from the original message, and sends the acknowledgment to those neighboring routers to which the original message was sent, excluding the link from which the sequencer acknowledgment was received. If the original message corresponding to the sequencer acknowledgment was buffered at this router waiting to be delivered, the message is then delivered to its client nodes.

Message sequencing for ordered multicasting of a message across a routing network

Resources are checkpointed in order to save the state of the resources. The resources can then be brought back to the same running state, during a restart procedure, by making use of the saved state. The determination of when to take a checkpoint or when to restart a resource is made by an entity, such as a cluster manager, external to the entity initiating or taking the checkpoint or performing the restart. The decision to checkpoint/restart a resource is provided by the cluster manager to a resource manager associated with the resource. This communication is facilitated by interfaces to the cluster manager provided by the resource manager.

Method, system and program products for managing the checkpointing/restarting of resources of a computing environment

Within a computer cluster usage reference counts are maintained for replicated databases within a computer cluster using cluster membership and cluster voting services. Such a method includes the maintaining of a local reference count for all open distributed data resources within a given node, tracking by a group services client of those nodes that have the open distributed data resources, and using cluster membership services to update the local reference counts for node failures.

Apparatus and method for tracking access to data resources in a cluster environment

A generalized search data structure is used to match consumers to events in event computing systems. The search data structure includes one or more paths from a root of the structure to one or more leaves of the structure. Each path has at least one level and each level corresponds to a filter attribute. The value of at least one filter attribute in at least one path is a don't care value indicating traversal of that path is guaranteed to proceed. In addition to following the path with the don't care value, one or more additional paths may also be followed. Thus, traversal of the search data structure may yield zero or more results, indicating that zero or more consumers match the specified event. Various optimizations of the search data structure are possible.

Method and system for matching consumers to events

A method and program product for managing membership of process groups of a distributed computing environment. Requests to alter membership of a first process group are received and presented to the first process group as a batched request. However, requests to change the membership of a second process group are received and presented to the second process group serially. Thus, the manner in which requests are presented can be different for various process groups. Additionally, different types of requests can be presented to the same process group in a differing manner. For instance, requests to join a process group can be presented as a batched request and requests to leave the process group can be presented serially, or vice versa.

Utilizing batch requests to present membership changes to process groups

A router within a network uses the data of a message received at the router to determine on which links out of the router the message needs to be forwarded. The router does not need any destination information from the message, and thus, the message need not include any destination information. Instead, the router uses an annotated search data structure to determine which links correspond to consumers interested in receiving the message. The message is sent only over those links.

Routing messages within a network using the data content of the message

A barrier synchronization system in a distributed computing environment. A group of members, including a plurality of related processes executing on one or more processors of the distributed computing environment, is provided a protocol having a dynamic number of synchronization phases. The protocol is voted on by one or more members of the group to determine how the protocol should proceed for the group of members. The protocol may complete successfully, continue to another synchronization phase or be rejected. The group of members determines how many synchronization phases the protocol is to include.

System for barrier synchronization wherein members dynamic voting

An application programming interface that unifies a plurality of mechanisms into a single framework. The interface includes a mechanism for communicating between members of a process group of related processes, and a mechanism for synchronizing the related processes of the process group. Additionally, the application programming interface may include mechanisms for managing membership of the process group or a processor group of processors, and/or a mechanism for controlling a group state value for the process group.

Application programming interface unifying multiple mechanisms

A barrier synchronization program product in a distributed computing environment. A group of members, including a plurality of related processes executing on one or more processors of the distributed computing environment, is provided a protocol having a dynamic number of synchronization phases. The protocol is voted on by one or more members of the group to determine how the protocol should proceed for the group of members. The protocol may complete successfully, continue to another synchronization phase or be rejected. The group of members determines how many synchronization phases the protocol is to include.

Program product to effect barrier synchronization in a distributed

Detecting the failure of the name server node and consulting a membership list of nodes in the domain to determine the crown prince (CP) node who is next in line to become the name server. The other available nodes in the domain periodically send recover messages to the CP node, and responsive to receiving the recover messages from all the other available nodes in the domain, the CP node perform a two phase takeover whereby the CP node becomes the name server for managing said processors in the domain. After the CP node becomes the name server, the other available nodes in the domain send data to the new name server necessary for the name server to manage the other available nodes in the domain. All request messages requesting management by the name server are stored locally until after the CP becomes the name server. The locally stored request messages are then processed by the other available nodes such that no request messages are lost during recovery.

Growing community of inventors

Elmsford, NY, United States of America

Tushar Deepak Chandra