Thursday, September 24, 2009

PMI = all is not a good setting for production

I am reminded occasionally when debugging production issues that setting the PMI level in WebSphere Application Server to "all" is not a good thing to do. At the "all" setting one can see an application exhibit negative behavior. I am also learning no two applications will always exhibit the same problem. Some applications crash and burn under the weight of PMI=all incapable of providing a response to any request. Other applications seem to continue to function nominally but the CPU for those processes seem to be considerably higher.

Finally, regardless of the PMI settings configured in the production environment it is imperative that all members of a cluster are set to the same values. Having some processes set to one level and other processes set to another results in higher CPU utilization from some JVMs and not others.

1 comment:

janglestrategies said...

Hi Alexandre

Whilst PMI=all is not a good setting for prod, would you advise that PMI is disabled completely in a prod environment or do the benefits of having at least some PMI stats outweight the overhead this might put on the system?

In particular, I am only looking to enable custome PMI stats for sessionobjectsize and nothing else but our so called experts are wary of even having this one setting on in case it slows down the system.