After installing and starting CICS on an LPAR, ECSA usage is increasing noticeably. A number of storage blocks with the header text "UVT large pool" are seen.
Component : CA ACF2 for z/OS
Component : CAIENF / CICS
Component: CA ENF/USS
"UVT Large Pool" is the CPOOL identifier that CA ENF/USS uses in a work area to handle USS security calls that it passes on to ACF2.
The UVT Large pool blocks are work areas allocated by ENF/USS, they are related to each OMVS callable service passed to ACF2. They are allocated using IBM service CPOOL. The storage is re-used when available but does not contract from its "high usage" mark. A high volume of concurrent USS requests in process can lead to increased ECSA consumption. Alternatively, if a lot of CICS regions start up at the same time and they access a lot of uss files for webservices, many of these work areas will be created at the same time, and will remain until the next IPL.