1. Administering JMS Resources for Oracle WebLogic Server
  2. Preface

Preface

This preface describes the document accessibility features and conventions used in this guide—Administering JMS Resources for Oracle WebLogic Server

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Conventions

The following text conventions are used in this guide:

Convention Meaning

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Advantages of JMS Clustering

The advantages of clustering for JMS include the following:

  • Load balancing of destinations across multiple servers in a cluster

    An administrator can establish load balancing of destinations across multiple servers in the cluster by:

    • Configuring a JMS server and targeting a WebLogic cluster. See Simplified JMS Cluster and High Availability Configuration.

    • Configuring multiple JMS servers and targeting them to the configured WebLogic Servers.

    • Configuring multiple JMS servers and targeting them to a set of migratable targets.

    Each JMS server is deployed on exactly one WebLogic Server instance and handles requests for a set of destinations.

  • High availability of destinations

    • Distributed destinations : The queue and topic members of a distributed destination are usually distributed across multiple servers within a cluster, with each member belonging to a separate JMS server. Applications that use distributed destinations are more highly available than applications that use simple destinations because WebLogic JMS provides load balancing and failover for member destinations of a distributed destination within a cluster. For more information on distributed destinations, see Configuring Distributed Destination Resources.

    • Store-and-Forward : JMS modules use the SAF service to enable local JMS message producers to reliably send messages to remote queues or topics. If the destination is not available at the moment the messages are sent, either because of network problems or system failures, then the messages are saved on a local server instance, and are forwarded to the remote destination as soon as it becomes available. See Understanding the Store-and-Forward Service in Administering the Store-and-Forward Service for Oracle WebLogic Server.

    • For automatic failover, WebLogic Server supports migration at the server level—a complete server instance, and all of the services it hosts can be migrated to another machine, either automatically or manually. See Whole Server Migration in Administering Clusters for Oracle WebLogic Server.

      WebLogic Server also supports automatic migration at the service level for JMS, where a failed service instance can be restarted in place on its current WebLogic Server JVM or migrated to another running JVM in the same cluster. This is termed 'service migration' and there are two approaches for configuring it based on how JMS is configured and targeted. For more information, see Migratable Target and Simplified JMS Configuration and High Availability Enhancements. The latter is recommended for new configurations.

  • Cluster wide, transparent access to destinations from any server in a cluster

    An administrator can establish cluster wide, transparent access to destinations from any server in the cluster by either using the default connection factories for each server instance in the cluster, or by configuring one or more connection factories and targeting them to one or more server instances in the cluster, or to the entire cluster. This way, each connection factory can be deployed on multiple WebLogic Server instances. Connection factories are described in more detail in Connection Factory Configuration.

  • Scalability

    • Load balancing of destinations across multiple servers in the cluster.

    • Distribution of the application load across multiple JMS servers through connection factories, thus reducing the load on any single JMS server and enabling session concentration by routing connections to specific servers.

  • Server affinity for JMS Clients

    When configured for the cluster, load-balancing algorithms (round-robin-affinity, weight-based-affinity, or random-affinity), provide server affinity for JMS client connections. If a JMS application has a connection to a given server instance, JMS attempts to establish new JMS connections to the same server instance. For more information on server affinity, see Load Balancing in a Cluster in Administering Clusters for Oracle WebLogic Server.

For more information about the features and benefits of using WebLogic clusters, see Understanding WebLogic Server Clustering in Administering Clusters for Oracle WebLogic Server.

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