Performance Management Guide

Expanding the Configuration

Unfortunately, every performance-tuning effort ultimately does reach a point of diminishing returns. The question then becomes, "What hardware do I need, how much of it, and how do I make the best use of it?" That question is especially tricky with disk-limited workloads because of the large number of variables. Changes that might improve the performance of a disk-limited workload include:

• Adding disk drives and spreading the existing data across them. This divides the I/O load among more accessors.
• Acquiring faster disk drives to supplement or replace existing ones for high-usage data.
• Adding one or more disk adapters to attach the current and new disk drives.
• Adding RAM to the system and increasing the VMM's minperm and maxperm parameters to improve the in-memory caching of high-usage data.

For guidance more closely focused on your configuration and workload, you can use a measurement-driven simulator, such as BEST/1.