LLA and VLF
Modules loaded by CICS from the DFHRPL (or dynamic LIBRARY concatenation) may be managed by the MVS LLA (library lookaside) facility.
LLA is designed to minimize disk I/O by keeping load modules in a VLF (virtual lookaside facility) dataspace and keeping a version of the library directory in its own address space.
LLA manages modules (system or application) whose library names you have put in the appropriate CSVLLA member in SYS1.PARMLIB.
There are two optional parameters in this member that affect the management of specified libraries: