In Memory Data Grid - IMDG, or Enterprise Data Grid - EDG
A set of space instances, typically running within their respective processing unit instances.
The space instances are connected to each other to form a space cluster.
The relations between the spaces define the Data Grid Topology.
Key Sentence: A set of connected space instances holding objects form a space cluster
A Data Grid with 3 Instances
Data Grid Topologies
Primary Backup Data Grid
A Data Grid with a primary instance and one or more backup instances.
Destructive operations (write, update and take) are applied to the primary instance, and are replicated to the backup instance either synchronously or asynchronously.
Key Sentence: Objects in primary instance are replicated to its backup instance/s
A Data Grid comprised of a primary instance with one backup instance
Partitioned Data Grid
Each Data Grid instance (partition) holds a different subset of the objects in the Data Grid.
When the objects are written to this Data Grid, they are routed to the proper partition, according to a predefined attribute in the object that acts as the routing index.
A Partitioned Data Grid with 3 Instances, each holding a different set objects
Routing
The mechanism that is in charge of routing the objects into and out of the corresponding partitions.
The routing is based on a designated attribute inside the objects that are written to the space, and is termed Routing Index.
Key sentence: Routing the mechanism that determines how object will be partitioned.
Routing in a partitioned Data Grid with 3 instances
Primary Backup Partitioned Data Grid
A partitioned Data Grid, with one or more backup instances for each partition. Each of the Data Grid instances (partitions) holds a different subset of the objects in the Data Grid, and replicates this subset to its backup instance/s.
A Primary Backup Partitioned Data Grid: 2 partitions, each replicates to one backup instance
For details about scaling a running space cluster in runtime see the Elastic Processing Unit section.
