Significant performance benefits can be realized by increasing the amount of memory that is 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 usage are just a few of the functions whose ease of use and performance can be improved when more memory is made available to them.
The following benefits can realized:
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 several factors, including potential I/Os to be eliminated, resource contention, workload, configuration, and tuning, clients must carefully consider whether their environment can benefit from the addition of memory to the software functions that are described in this IBM Redpaper™ publication.
This paper describes the performance implications of increasing memory in the following areas:
DB2 buffer pools
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
DFSort I/O reduction
Fixed pages and fixed large pages