What is WebSphere eXtreme Scale (WXS)

"WebSphere eXtreme Scale is an elastic, scalable, in-memory data grid. It dynamically caches, partitions, replicates, and manages application data and business logic across multiple servers.r" - IBM documentation

• WXS is dynamic
• It can dynamically create new servers and remove the number of servers
• It can add or reduce the network throughput on the fly
• It is self-healing (autonomic) and can recover from failures
• It has partitions of data
• It has partition (shards) to spread out the data across servers
• It has replication of these shards against failure
• It has data structure (catalog) and special SQL support to the operations and management of these partitions (shards)
• It is a write-behind cache that serves as a front-end cache for the database backends
• The data grid can be run from hundreds of JVM instances and therefore very large
• The data grid can be hardened using disk files or database or both
• Data grid is a key-value pair for data storage and retrieval

What is NOT WebSphere eXtreme Scale?

• It is not an in-memory database - in-memory database is not as resilient aand high performance as WXS
• It is not an object-relationship mapper (in other words, database and data grid consistency must be maintained by the application or the mapper)