em/initial_size_MB
The amount extended memory for all working processes.Under Windows, further memory is assigned dynamically as needed, and you can also set this amount.Ensure that the pool is 10 to 15 times as big as ztta/roll_extension. The exact value depends on the available swap space and the number of users in the host system.
ztta/roll_extension
Specifies how much extended memory can be allocated from the pool to one user context.If ztta/roll_extension_dia or ztta/roll_extension_nondia are not set (DEFAULT.PFL or instance profile), the value in ztta/roll_extension (old procedure) applies for ALL work process types.If, on the other hand, ztta/roll_extension_(non)dia is set, the value in ztta/roll_extension is overwritten for the work process type in question.If the value is exceeded, heap memory is allocated. The work process is assigned only to this user context and is no longer available for other user contexts, since it is switched to the PRIV mode