DFS3834W ALTERNATE IS (IN DANGER OF) FALLING BEHIND

Explanation

The IMS XRF alternate subsystem has fallen behind or is in danger of falling behind in the processing of log records produced by the active IMS XRF subsystem.

Statistics are gathered over one minute intervals to determine if either of these conditions has occurred. When either condition occurs, the message is highlighted and frozen on the system console until the condition clears up.

The falling behind condition might extend the time of a takeover should one be necessary.

System action

The IMS alternate continues tracking the active and can catch up over time. This message is frozen and highlighted on the system console until the alternate has caught up sufficiently. At that time, the message is no longer highlighted and rolls off the screen.

Operator response

Alert the system programmer of continued "in danger" messages so that appropriate preventive action can be taken. When the alternate is falling behind, the elapsed time of a takeover can be extended. You can estimate the time lag behind the active by entering the /DISPLAY HSB command.

System programmer response

Determine the cause of the falling behind periods, take any appropriate preventive actions, and contact IBM® Software Support for assistance, if necessary.

Some actions to consider are:
  • Assure a good balance between the use of Short and Long Message Queue data sets.
  • Assure that the message queues are not filling up for a device that has been turned off.
  • Increase the number of Message Queue buffers assigned to the Active and XRF Alternate systems.
  • If you are experiencing high I/O rates on any of the devices that contain the Message Queue data sets, consider splitting up those data sets with the highest I/O activity across different devices.