There’s not really a way you can performance tune an iSeries without knowing what’s going on on the system itself. You need to know what sort of jobs are running, how much cpu those jobs are using how much memory the machine has, how much disk the machine has, how much disk is used on the machine etc.
Do you have performance tools installed on the machine? Do you have the performance adjuster switched on (system value QPFRADJ)?
Ideally you should use performance tools to gather information about the system’s performance and based on the information from performance tools then you can adjust various system settings to tune the system to handle the workload that performance tools measured.
As noted above, there is no “easy” way to tune any system including iSeries. The iSeries is more capable of being tuned than most other systems, but it does take knowing what you’re doing.
Performance Tools won’t help if you don’t know what you’re doing. And the performance adjuster is not a good idea unless you first tune your system to account for your general workload types — it has as good a chance of making things worse as better, perhaps more than an even chance because it will be using CPU and not have the appropriate resources to be effective.
There are no simple CL or other programs for it.
You can start by reviewing the performance topic in the Information Center. After a review, learn the details by studying the Work Management (PDF) guide.
Once your basic work management structure is in place, then turn on the performance adjuster. Then begin reviewing results, perhaps with Performance Tools, but other choices are available.