Dump space (in kilobytes)

Dump space for the coupling facility.

You can define only one dump space in each coupling facility; however, that dump space can contain several structure dump tables. IBM recommends that you specify 5% of the available storage in a coupling facility for dump space. If you do not specify any coupling facility dump space, none will be allocated and no structures in the coupling facility can be dumped.

An alternative method to the 5% "rule of thumb" for defining the amount of dump space is to allow all coupling facility storage that is not dedicated to structures to be used as dump space. Using this method maximizes the use of coupling facility storage while ensuring that there is enough coupling facility storage space available for all structures defined in a given CFRM policy. This method allows you to define more that 5% of coupling facility storage for structure dumping if there is excess storage available in the coupling facility.

Calculate the amount of storage available for dump space as follows:

  1. Determine the amount of coupling facility storage dedicated for use by structures. This includes storage for structures that might normally reside in other coupling facilities but that can be relocated, in failure scenarios, to the coupling facility for which this calculation is being performed. From your CFRM policy, add together the values of the maximum sizes for the structures that contain the coupling facility name in their preference list. The result is the total storage required by structures in 1K units.
  2. Determine the amount of coupling facility storage that can be used for structure dumps by subtracting the total storage required for structures from the total amount of coupling facility storage.
  3. If the amount of storage available for structure dumps is insufficient, consider reconfiguring your coupling facility to obtain additional storage space for structure dumps.

Valid values: 1 - 6 decimal digits (in kilobytes)