The topology defines the relative location of a data store and
its messaging engine, as well as
the relationship with otherdata stores.
You
have several options for the relative location of a data store and
its messaging engine. The topology
also defines the relationship of a data store with
other data stores.
The following principles apply:
- The default embedded Cloudscape
Version 10.1.x (Derby) data store always
runs in the same server process as the messaging engine.
- For a messaging engine that can
failover within a WebSphere cluster, you must ensure that any server that
the policy might choose to run the messaging engine can
gain access to the data store.
The embedded Cloudscape
Version 10.1.x (Derby) data store is
not supported for a messaging engine running
in a WebSphere cluster. Use either Cloudscape Version 10.1.x (Derby) in Network Attach
mode, or an alternative relational database management system.
To support high availability (HA), you can configure the data store as
follows:
- Configure the data store to
use a shared, network mounted, file system. Ensure that you protect against
the file system being a single point of failure.
- Configure the data store to
use a remote database server. Ensure that you protect against a failure of
the database server.
- Configure the data store to
use a "shared disk" in an HA cluster. The HA cluster performs failover
of the data store and, optionally,
can coordinate failover of the messaging engine .