DX Application Performance Management

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  • 1.  PMI disabling/enabling in WAS for Introscope - Advantages and Disadvantages

    Posted Jun 13, 2012 01:57 PM
    We have Wily APM v9.1.0.1 (Introscope Agent) in non-prod eng. The middleware group is very much interested in finding out what are the advantages and disadvantages of turning ON PMI in the jvm (WAS) while running Introscope agent. And what are advantages and disadvantages of turning OFF PMI.


  • 2.  RE: PMI disabling/enabling in WAS for Introscope - Advantages and Disadvant

    Posted Jun 13, 2012 03:49 PM
    Basically, by turning on the PMI metrics in a WAS system, you will be able to monitor performance parameters like DB connection pool usage, GC, heap usage, web container threads etc.





    mparikh wrote:

    We have Wily APM v9.1.0.1 (Introscope Agent) in non-prod eng. The middleware group is very much interested in finding out what are the advantages and disadvantages of turning ON PMI in the jvm (WAS) while running Introscope agent. And what are advantages and disadvantages of turning OFF PMI.


  • 3.  RE: PMI disabling/enabling in WAS for Introscope - Advantages and Disadvant

    Posted Jun 13, 2012 05:06 PM
    Well, apparently with JMX turned on and IBM pushing towards it Introscope can get most all of PMI metrics without enabling it. It's basically going through the backdoor under the PMI and grabbing those same exact metrics. PMI is sugarcoats the JMX values. So, for our scenario it seems like we are going to turn off PMI and stick with JMX.

    Comments, suggestions, feedback???

    Thanks


  • 4.  RE: PMI disabling/enabling in WAS for Introscope - Advantages and Disadvant

    Posted Jun 25, 2012 01:03 PM
    we made different bad experiences with PMI:

    - The PMI documentation is very simply Bad.
    - The way how you need to configure PMI if you want to do it with a config file is very hard to manage because IBM is relaying on Numbers instead of Names and there as well a very bad documentation.
    - At least the Wily 8.2 WebSphere Power Pack is not fully supporting all PMI modules especially because IBM is not keeping a standard and i would say: IBM playing around with it instead of offering a propper service. (it was at one point even stated as a deprecated service)
    - We had multiple incidents and issues using PMI:
    1) deadlock condition with one of the metrics related to the session module
    2) metric explosion because of the ejb and servlet PMI module which does not realy give you any benefit comparing to what you get out of BCI
    3) users which enabled ALL PMIs in the WebSphere console which caused as well a metric explosion
    and other issues i forgot because most of the things we just disabled since almost 2 years

    - There are PMI metrics called PercentUsed PercentMaxed which don't work anymore since IBM introduced some fix packs and released loads of different APARs for "fixing" it.
    - PMI is known for partially heaving a huge performance impact

    So i personally think its actually a bad idea and there should be a strategy from moving away from it.

    I think the JMX is the way further especialy as its a common JAVA standard and is not relying on proprietary IBM implementations.