Does anyone have some guidance on tuning ARS_NUM_DBSRVR? What type of degradation happens when the number of connections exceeds efficiency? We currently went from the default 4 to 25. We are seeing more failing transaction without pinpointing any other change than this one. Could we have set it too high?
What's the error message from DB2? There are lots of situations that can create failed queries. Having too many database servers for CMOD is just going to gobble up some RAM that could be better used elsewhere.
When tweaking database parameters, I usually keep my changes to a maximum of 50% of the existing setting, and repeat this process until I find out if performance is improving. If performance isn't improving, I roll back and look elsewhere.