Abstract: A security policy process which provides role-based permissions for hierarchically organized system resources such as domains, clusters, application servers, and resources, as well as topic structures for messaging services. Groups of permissions are assigned to roles, and each user is assigned a role and a level of access within the hierarchy of system resources or topics. Forward or reverse inheritance is applied to each user level-role assignment such that each user is allowed all permissions for ancestors to the assigned level or descendants to the assigned level. This allows simplified security policy definition and maintenance of user permissions as each user's permission list must only be configured and managed at one hierarchical level with one role.

Abstract: 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.

Abstract: A method for replicating data in a distributed computer environment wherein a plurality of servers are configured about one or more central hubs in a hub and spoke arrangement. In each of a plurality of originating nodes, updates and associated origination sequence numbers are sent to the central hub. The hub sends updates and associated distribution sequence numbers to the plurality of originating nodes. The hub tracks acknowledgments sent by nodes for a destination sequence number acknowledged by all nodes. Thereafter, a highest origination sequence number is sent from the central hub back to each originating node.

Abstract: One application of clustered computer systems is to support failover of applications and shared resources. Another is to support scalable or fault-tolerant distributed applications. The present invention utilizes a higher-level clustering mechanism (a multi-cluster) overlayed on top of multiple underlying clusters (subclusters) to extend their capabilities. In the described embodiment, subclusters supporting application and shared resource failover across a smaller number of nodes is overlayed with a multi-cluster supporting a larger number of nodes. The multi-cluster manages cluster-level communication among nodes, and the subclusters directly manage only the shared device and application resources which they are permitted to control. It is possible to move resources between nodes which reside in different subclusters. The multi-cluster layer also externalizes interfaces similar to those of the subclusters, providing application compatibility.

Abstract: A cluster system is treated as a set of resource groups, each resource group including an highly available application and the resources upon which it depends. A resource group may have between 2 and M data processing systems, where M is small relative to the cluster size N of the total cluster. Configuration and status information for the resource group is fully replicated only on those data processing systems which are members of the resource group. A configuration object/database record for the resource group has an associated owner list identifying the data processing systems which are members of the resource group and which may therefore manage the application. A data processing system may belong to more than one resource group, however, and configuration and status information for the data processing system is replicated to each data processing system which could be affected by failure of the subject data processing system.

Abstract: A cluster system is treated as a set of resource groups, each resource group including an highly available application and the resources upon which it depends. A resource group may have between 2 and M data processing systems, where M is small relative to the cluster size N of the total cluster. Configuration and status information for the resource group is fully replicated only on those data processing systems which are members of the resource group. A configuration object/database record for the resource group has an associated owner list identifying the data processing systems which are members of the resource group and which may therefore manage the application.

Abstract: A clustered computer system provides both speed and reliability advantages. However, when communications between the clustered computers is compromised those same computers can become confused and corrupt database files. The present method and apparatus are used to improve the management of clustered computer systems. Specifically, the system expands the number of nodes available for failover conditions.

Abstract: A method for replicating data in a distributed computer environment wherein a plurality of servers are configured about one or more central hubs in a hub and spoke arrangement. In each of a plurality of originating nodes, updates and associated origination sequence numbers are sent to the central hub. The hub sends updates and associated distribution sequence numbers to the plurality of originating nodes. The hub tracks acknowledgments sent by nodes for a destination sequence number acknowledged by all nodes. Thereafter, a highest origination sequence number is sent from the central hub back to each originating node.

Abstract: A node failure recovery mechanism for use in a data replicating system in a distributed computer environment wherein a plurality of servers are configured about one or more central hubs in a hub and spoke arrangement. In each of a plurality of originating nodes, updates and associated origination sequence numbers are sent to the central hub. The hub sends updates and associated distribution sequence numbers to the plurality of originating nodes. The hub tracks acknowledgments sent by nodes for a destination sequence number acknowledged by all nodes. Upon failure of a node, a node failure recovery method may be used to enable a “buddy” node to help the failed node gain readmission to a distribution group.

Abstract: A cluster system is treated as a set of resource groups, each resource group including a highly available application and the resources upon which it depends. A resource group may have between 2 and M data processing systems, where M is small relative to the cluster size N of the total cluster. Configuration and status information for the resource group is fully replicated only on those data processing systems which are members of the resource group. In the event of failure of a data processing system within the cluster, only resource groups including the failed data processing system are affected. Each resource group having a quorum of its data processing systems available continues to provide services, allowing many applications within the cluster to continue functioning while the cluster is restored.

Abstract: A method for replicating data in a distributed computer environment wherein a plurality of servers are configured about one or more central hubs in a hub and spoke arrangement. In each of a plurality of originating nodes, updates and associated origination sequence numbers are sent to the central hub. The hub sends updates and associated distribution sequence numbers to the plurality of originating nodes. The hub tracks acknowledgments sent by nodes for a destination sequence number acknowledged by all nodes. Thereafter, a highest origination sequence number is sent from the central hub back to each originating node.

Abstract: Configuration changes are dynamically applied to a cluster multiprocessing system by enqueuing a configuration change event. When the configuration change event is processed, the prior configuration is backed up and each software component applies a relevant portion of a configuration change transaction in an ordered, synchronized manner. Each software component applies its portion of the transaction either by reinitialization or a logged transition operation. If the configuration change transaction fails, the software components roll back the portions, of the configuration change already applied in an ordered, synchronized manner to restore the prior configuration. Multiple events for different configuration changes may be enqueued.