Hi Chris
Few things I would monitor to see if you are seeing any oversubscription is
1)Increasing input drops and output drops on a regular basis. This can be collected using show interfaces
2)In the following output, Rx-No-Pkt-Buff, flow control is something I would watch for as well. But keep in mind these will increment when there are traffic bursts even in non-oversubscribed cards.
4507-1# show interface GigabitEtherent 4/7 counters detail
Port Rx-No-Pkt-Buff RxPauseFrames TxPauseFrames PauseFramesDrop
Gi4/7 1956 35648 4854 0
http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a008015bfd6.shtml#Rx-No
I am sure there are MIBs to poll all these. But as a best practice, its always recommended to use non-oversubscribed ports for server farms. The oversubscribed cards are primarily designed for bursty traffic deployments such as gigabit to desktop