Use the JESMsgSize statement to specify the maximum mail message size accepted from a JES spool file, in thousands of bytes.
Tip: Set this value for the largest mail message expected and add enough room for future growth.
.-JESMsgSize 0----. >>-+-----------------+----------------------------------------->< '-JESMsgSize size-'
Restriction: The JESMsgSize value must be less than or equal to the JESJobSize value.