Thanks for the comprehensive reply. Briefly I would say that we care about availability more than performance, though both are important. We're running somewhere on the order of 2000 VMs w/ ESX with some bare metal systems running database clusters. We have a separate team that manages the hardware infrastructure and they have their own monitoring and alerting system. I'm mostly concerned about preventing downtime for the application cluster, alerting the right people via the right means (chat, email, pagerduty) when something does go down, and getting some high resolution graphs for analysis.