CICS regions see increased usage of ECSA storage by ACF2

Products

• ACF2
• ACF2 - z/OS
• ACF2 - MISC

Issue/Introduction

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. 

Environment

Component : CA ACF2 for z/OS

Component : CAIENF / CICS

Component: CA ENF/USS

Resolution

"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.