By default, CHUNK_JOB_SIZE is not enabled.
Begin Queue QUEUE_NAME = chunk PRIORITY = 50 CHUNK_JOB_SIZE = 4 End Queue
Begin Queue
QUEUE_NAME = chunk
PRIORITY = 50
CHUNK_JOB_SIZE = 4
End Queue
After adding CHUNK_JOB_SIZE to lsb.queues, use badmin reconfig to reconfigure your cluster.