This question is pretty vague, what are you trying to identify?
Perhaps you could reference the "Resource Pool and Cluster Maximums" section in the relevant documentation;
http://www.vmware.com/pdf/vsphere4/r40/vsp_40_config_max.pdf
http://www.vmware.com/pdf/vsphere4/r41/vsp_41_config_max.pdf
http://www.vmware.com/pdf/vsphere5/r50/vsphere-50-configuration-maximums.pdf
http://www.vmware.com/pdf/vsphere5/r51/vsphere-51-configuration-maximums.pdf
http://www.vmware.com/pdf/vsphere5/r55/vsphere-55-configuration-maximums.pdf
Cheers,
Jon