WebSphere® Application Server provides integrated high availability (HA) support in which system subcomponents, such as the transaction service, are made highly available. An HA policy provides the logic that governs the manner in which each WebSphere Application Server HA component behaves within the overall HA framework. For the transaction service, the transaction HA policy provides the logic to determine which servers own a recovery log at any time.
Typically, transaction policies assign ownership of a recovery log to the server that originally created it (the home server) and that server can then use the recovery log for both recovery and normal transactional activity. In the event that the home server is unavailable or fails, ownership can pass to a peer server to undertake recovery processing.
Conceptually, a policy can be thought of as consisting of two key components, a policy type and a policy configuration.