
318 WebSphere Application Server V8.5 Concepts, Planning, and Design Guide
Calculating availability by using the following formula:
Availability = (MTBF/(MTBF + MTTR)) X 100
where:
MTBF Is the mean time between failure
MTTR Is the maximum time to recovery
Keep in mind that the overall infrastructure is available only if all the components are
available. A WebSphere Application Server infrastructure consists of several components
such as load balancers, HTTP servers, application servers, and database servers. Availability
is determined by the weakest component.
For most of the environment components, several degrees of high availability exist in ...