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Recoverability

CA DRAS is a multi-tasking server. It consists of a main task, a logging task, a special processing task, and one or more normal request processing tasks. The number of normal processing tasks is specified with the SET THREADS command in the configuration file.

If an ABEND occurs on the main task, the CA DRAS started task ends and must be restarted. But if the ABEND or other critical error occurs on a sub-task, the impact on the main task depends upon the particular sub-task. If a normal request processing task abends it is removed but CA DRAS can still continue to process in most cases.

Logging Subtask

Although CA DRAS can continue to run without the logging task, it is not recommended. Without logging, it is impossible for you to know if work is being done or if errors are occurring. If the main task detects that the logging task has abended, the following message is written to the JES log, and a user ABEND is issued to terminate the region.

CAHFMTK023S Log task ABEND. CA DRAS is terminating.

Additionally, user ABEND U0100 is issued to force the region down.

The ABEND reason code is set to the ABEND code of the original problem. For example, if the logging task abended with a S0C4, the message is:

IEA995I SYMPTOM DUMP OUTPUT 238                
..USER COMPLETION CODE=0100 REASON CODE=400C4000

Special Processing Subtask

Some of the work done by CA DRAS must be serialized. A special processing subtask is started for this purpose. If it abends, CA DRAS cannot continue, and you can see the following message:

CAHFMTK025S Critical task ABEND. CA DRAS is terminating

Additionally, user ABEND U0300 is issued to force the region down.

The ABEND reason code is set to the ABEND code of the original problem. For example, if the special processing task abended with a S0C4, the message is:

IEA995I SYMPTOM DUMP OUTPUT 238                
  USER COMPLETION CODE=0300 REASON CODE=400C4000

Normal Processing Subtasks

When you configure CA DRAS, you specify the number of normal processing subtasks with the SET THREADS(nn) command. If one of these subtasks abends, CA DRAS alerts you with a message to SYSLOG.

For example, you specify SET THREADS(12) in your configuration file. As a result, CA DRAS attaches 12 subtasks. If one of them abends, CA DRAS issues the message:

CAHFMTK026S Processing thread ABEND. 11 of 12 threads still running

You can never see a CAHFMTK026S message that says "0 of 12 threads still running." Instead, you can see:

CAHFMTK027S All processing threads have ABENDED. CA DRAS is terminating

Additionally, user ABEND U0400 is issued to force the region down.

The ABEND reason code is set to the ABEND code of the last failing subtask. For example, if the processing task abended with a S0C4, the message is:

IEA995I SYMPTOM DUMP OUTPUT 238                
  USER COMPLETION CODE=0400 REASON CODE=400C4000