High availability
With high availability, WebSphere® eXtreme Scale provides reliable data
redundancy and detection of failures.
Replicas and shards
With eXtreme Scale,
an in-memory database or shard can be replicated from one Java™ virtual
machine (JVM) to another. A shard
represents a partition that is placed on a container. Multiple shards
that represent different partitions can exist on a single container.
Each partition has an instance that is a primary shard and a configurable
number of replica shards. The replica shards are either synchronous
or asynchronous. The types and placement of replica shards are determined
by eXtreme Scale using a deployment
policy, which specifies the minimum and maximum number of synchronous
and asynchronous shards.