Hi Phani
This is what I could find doing an internal search:
* disable_resource_pool_perf_metrics - This is the major one for collection time improvements. This disables all metrics of type ‘PERF’ (visible in the GUI) on resource pools. The vCenter has to go to the database to get these metrics, so any IO limitations with the database will be exposed. This also disables perf metrics on Virtual Apps (a special type of resource pool that we track separately).
* disable_vm_system_perf_metrics - Turn off internal metric collections.
* disable_host_system_perf_metrics - This is another minor optimization. If no metrics on the ‘System’ node (or its children) are being used, this can be set to ‘yes’ to save a little bit of memory and a little bit of time in collection.
* disable_array_metrics - Minor optimization. This disables collection of host virtual switches, host services and VM guest disks. Additionally, if any status info metrics were turned on in the mondef.cfg, it disables them as well.
* use_guest_name_for_source - When set to 'yes' it will use the vm ip address or guest name. By default it's set to 'no and it's using the VM name as displayed in vSphere.
I believe the following article could also be helpful: Tuning vmware probe performance
iulian