Based on the specifications you assigned to the DORMANCY= parameter on the MASDEF statement, the member that just had checkpoint access will not be allowed access for a period of time. This dormant period allows other members a time of “non-contended” access. Minimally, to assure access of the checkpoint by other members, DORMANCY= should be set to a value not less than the sum of the HOLD= specifications for all other members. See Member-specific parameter recommendations for performance recommendations for setting this parameter.