Environment Services System Services (ESSS) is a limited-function, MVS/ESA system address space that provides MVS services to CICSPlex® SM components. In particular, ESSS owns all of the MVS/ESA data spaces on an MVS image, so that they can exist independently of CMASs and MASs, yet remain accessible by both. The benefit of this arrangement is that the CICSPlex SM data accumulating in the data spaces is not vulnerable to events in the MAS and CMAS components. ESSS also plays a part in some aspects of communication between a CMAS and any NetView instance on the same MVS image as the CMAS.
There is one instance of ESSS for each version or level of CMAS
on any MVS image.