Just a bunch of link s on this topic:

http://www.settlersoman.com/vmware-vsphere-basics-understanding-resource-pools/

http://pubs.vmware.com/vsphere-50/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-50-resource-management-guide.pdf

http://www.yellow-bricks.com/2010/02/22/the-resource-pool-priority-pie-paradox/

http://www.yellow-bricks.com/2010/12/14/shares-set-on-resource-pools/

http://www.yellow-bricks.com/2010/02/24/custom-shares-on-a-resource-pools-scripted/

http://www.settlersoman.com/vmware-vsphere-basics-understanding-resource-pools/

http://download3.vmware.com/vmworld/2012/top10/vsp1683.pdf