Triggers for recovery

Situations from which solution recovery is necessary

Solution recovery is the process of returning the system to a state from which operation can be resumed. It encompasses a set of activities that address system failure or system instability that can be triggered by unforeseen circumstances.

You may need to perform solution recovery activities for the following circumstances:

• Hardware failure

  Abnormal termination or system down can be caused by a power outage or catastrophic hardware failure. This can cause the system (all if not most JVMs) to stop.

  In the case of a catastrophic hardware failure, the deployed solution may enter an inconsistent state on restart.

  Hardware failures and environmental problems also account for unplanned downtime, although by far not as much as the other factors.

  You can reduce the likelihood of hardware failures and environmental problems by using functions such as state-of-the-art LPAR capabilities with self-optimizing resource adjustments, Capacity on Demand (to avoid overloading of systems), and redundant hardware in the systems (to avoid single points of failure).

• System is not responsive

  New requests continue to flow into the system but on the surface it appears that all processing has stopped.

• System is unable to initiate a new BPEL process instance

  The system is responsive and the database seems to work correctly. Unfortunately, the new BPEL process instance creation is failing.

• Database, Network or Infrastructure Failure

  In the case of fundamental infrastructure failure, the solution may require administration to restart/resubmit business transactions after the infrastructure failure is resolved.

• Poor tuning or a lack of capacity planning

  System is functional but is severely overloaded. Transaction time-outs are reported and there is evidence of an overflow of the planned capacity.

  Incomplete capacity planning or performance tuning can cause this type of solution instability.

• Defects in application module development

  The modules that are part of a custom developed solution can have bugs. These bugs can result in solution instability and failed services.

  Bugs in a custom developed solution can result from a variety of situations, including (but not limited to) the following:

  • Business data that was not planned for or unforeseen by the application design.
  • An incomplete error handling strategy for the application design.

    A detailed error handling design can reduce solution instability.

• WebSphere® software defect

  A defect in the WebSphere product causes a backlog of events to process or clear.