Benefits of Configuring More Memory in the IBM z/OS Software Stack

Significant performance benefits can be experienced by increasing the amount of memory assigned to various functions in the IBM® z/OS® software stack, operating system, and middleware products. IBM DB2® and IBM MQ buffer pools, dump services, and large page exploitation are just a few of the functions whose ease of use and performance can be improved when more memory is made available to them.

These benefits can include:

Reduced I/O operations
Reduced CPU usage
Improved transaction response time
Potential cost reductions

Although the magnitude of these improvements can vary widely based on a number of factors, including potential I/Os to be eliminated, resource contention, workload, configuration, and tuning, clients should carefully consider whether their environment could benefit from the addition of more memory to the software functions described in this IBM Redpaper™ publication.
This paper describes the performance implications of increasing memory in the following:

DB2 buffer pools
DB2 tuning
IBM Cognos® Dynamic Cubes
MDM with larger DB2 buffer pools
Java heaps and Garbage Collection tuning and Java large page use
MQ v8 64-bit buffer pool tuning
Enabling more in-memory use by IBM CICS® without paging
TCP/IP FTP
DFSort I/O reduction
Fixed pages and fixed large pages