Hi jlegg,
You can use the performance counters available on the host and over the datacenter object.
Some things to think of are;
How many guests are on the host? (What's the physical to vCPU count on the host?)
Is there enough resources on the guest to provide enough resources?
Is the issue RAM related? If so check the hardware allocation and the reservation and limit for the guest OS.
Is the application JAVA? With some JAVA apps it can be a big memory drain on the system.
Do you have sufficient network bandwidth available for the VM's on the host?
-Check your vSwitch and be sure the systems LAN has sufficient bandwidth.
Is the guest OS in a resource pool with out enough resources?
Is the VMware tools installed? (are they out dated possibly by an update?)
Are you using nested resource pools?
Pretty much using the performance monitors on both the OS and also with your VIC you can identify the bottleneck.
You said CPU and RAM look good on the OS level, check the network bandwidth in Task mgr too.
It may be that there is excessive competition for the Host or RS-Pool on a resource by it's guests.
From personal experience the application slowdowns I've seen have been more often then not RAM first and second CPU related.
I've seen incorrectly assigned hardware RAM settings with conflicting reserve / limits that caused massive application issues.
Hope that helps,
-Eric
