PMDF System Manager's Guide
PMDF-REF-6.0

The system's heap size (datasize) must be enough to accomodate the Dispatcher's thread stack usage. For each Dispatcher service compute STACKSIZE*MAX_CONNS, and then add up the values computed for each service. The system's heap size needs to be at least twice this number.

To display the heap size (i.e., default datasize), use the csh command

# limit

# ulimit -a

# sysdef