WebSphere eXtreme Scale (formerly Data Grid), Version 6.1
             Operating Systems: AIX, HP-UX, Linux, Solaris, Windows


ObjectGrid overview

ObjectGrid is a grid-enabled, memory database for use with applications that are written in Java. ObjectGrid has transaction processing capabilities. You can use ObjectGrid as an in-memory database or to distribute data across a network.

With ObjectGrid, persistence is implemented through memory-to-memory replication, which you can configure to be synchronous, asynchronous, or a combination of the two. Although you cannot directly push state to disk, you can push data to disk by using plug-ins from an independent software vendor.

ObjectGrid provides vertical scalability by judicious use of threading. You can accomplish horizontal scalability by partitioning the data. A partition is synonymous to a hash column, where all data that is hashed to the specific column is hosted in a specific partition. A partition is made up of exactly one primary and a configurable number of replicas. These pieces of a partition are called shards. A single Java Virtual Machine (JVM) might host many partitions, but never more than one shard from the same partition. Very large sets of data can be stored in-memory across large numbers of JVMs.

Self-contained grid

ObjectGrid is packaged as several Java archive (JAR) files. When you are running ObjectGrid, the objectgrid.jar file is generally all that is required. You can use additional JAR files for prerequisite utilities like the cglib.jar file that might also be required. Optionally, you can use the ogstreamquery.jar file for the stream query support.

Self-organizing grid

With ObjectGrid, partitions are organized across a network of available JVMs based on the policies that are specified in the deploymentPolicy.xml file. The deploymentPolicy.xml file is a policy file that is used to describe the function of ObjectGrid. The primary of a partition can never be located in a JVM with one of its replicas. Additionally, the primary and replica cannot share a network interface card (NIC), unless specified in the policy. With zone support, you can create more sophisticated configurations to control placement across data centers. You can easily manage grids of thousands of partitions using a handful of optional placement rules.

Self-repairing grid

With the self-organizing ability, ObjectGrid can also self-repair. As servers leave the grid, the replica count is maintained. If a server that is holding a shard for a partition fails, the shard is recreated on an existing server automatically if possible. If the application specifies a primary and two replicas for each partition, the primary and replica count are automatically maintained as the failures occur. Failure detection is provided by the high availability manager in WebSphere Application Server. High availability is available if you install ObjectGrid in an environment containing WebSphere Application Server, or if you install ObjectGrid in other server environments. For more information, see Supported environments .




Related concepts
Supported environments
Related tasks
Using the Installation wizard to install ObjectGrid
Concept topic    

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Last updated: Oct 30, 2009 6:11:50 PM EDT
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