For example, you have a MAS where you specify:

SPOOLDEF FENCE=(ACTIVE=YES,VOLUMES=2)

Member A has spool affinity for volumes 1,2, and 3. Member B has spool affinity for volumes 1,2, and 4. A job converts on Member A and uses volumes 1 and 3. The job then executes on Member B. The job will potentially use space from three volumes before the fencing limit of 2 is reached. Because Member B does not have affinity for volume 3, the job will be allowed to get spool space from Volume 1 and either Volume 2 or 4 before the fencing limit is reached. A similar situation to this could occur if all spool volumes with affinity for the member temporarily fill and a job begins using space from a volume without affinity for the member.