Trade-offs between I/O controlled by IMS and paging

When you are choosing between I/O controlled by IMS and paging, you should consider several trade-offs.

General buffer pool considerations
Small tuned pools in IMS tend to minimize paging. In addition, because paging is not controlled by the IMS system, it can escalate dramatically in a storage-constrained environment.
IMS log buffers
When selecting the IMS online log data set (OLDS) block size and number of buffers in order to minimize system log I/O, similar concepts apply from general buffer pool considerations.
Using Library Lookaside under z/OS
As an alternative to IMS program loading with z/OS Program Fetch, you can specify the use of the z/OS service Library Lookaside (LLA). LLA is the recommended method for managing dynamically loaded program libraries.
Guidelines for application program preload in DB/DC and DCCTL environments
The preload option is commonly used for high-activity programs that do not use a large amount of virtual storage. You specify the names of the modules to be preloaded in member DFSMPLxx in the IMS.PROCLIB data set.

Parent topic: Initializing z/OS and IMS parameters for tuning