i have also a similar setup like you, c7000 with g7 blades...
so basic thing in the HP-VC is to enable smart link in the VC, ie for when you define each VLAN in the VC you need to enable this.This feature is very similar to the Uplink Failure Detection (UFD) that is available on the HP GbE2, GbE2c and most ProCurve switches. In Cisco switches called Link State Tracking. This will detect the uplink failures
we can use the both the hp-vc in active active mode, and we will take each flexnics from the each LOM (each LOM will connect to each VC that is VC in bay 1 and bay2) and we attach to the vSS or vDS.... example for a virtual switch you have 4 pnics 2 of them will be going to VC1 and other 2 will be going to VC2.
a network enabled with Smart Link automatically drops link to the server ports if all uplink ports lose link.
So how will the esx detect the pnic failures.... and uplink failures ?
case 1- HP -VC directly connected to the core switch no TOP of rack switch
when you set the failure detection policy as "link status.." the esx will detect the pnics failures inside the LOM.. or HP-VC issue. or any VC uplink failure or core switch failure. here the smart link works perfectly.
but this will work in the situation where your HP-VC is directly connected to the core switch.
in this case you dont need any beacon probing...and more over.. the in the core switch either UFD/LST will be configured..
So when we can enable becon probing... in order to work. this in a vswitch there should be more than 3 pnics and all that pnics should be connected to the same broadcast domain.. here in this case the pnics should be connected to the VC1 or VC2... so in short for a vswitch you need to have atleast 3 + pnics..total.. i dont think it will be.. required.... it is very rare we use ..refer the below.. the VC smart link feature and esx failure detection policy LINK STATUS is enough
case 2- Generally there will be TOP of rack switches...so the HP-VC will be connected to the TOP of rack swithch and then from the TOP of rack it will be connected to the core switch.
In this case.. when the TOP of rack uplink fails...or the core switch ports fails... the SMART LINK in the VC wont detect and the esx also wont detect.. so PACKET LOSS !!
Now, how will the esx will detect in this case... here we can use beacon probing... but as i mentioned in the case 1, we need more than 3 pnics... in that vswitch... again it wont be feasible... and good idea... VMware provided.. a solution... thats it... but it is not mandatory we need to use or it will give better...result.. beacon probing will be slower when compared to the UFD/LST...
in short... and in practical ...we need to use LST for cisco and UFD for hp and for avaya... i dont know.. defnitly there will be some...?
for a sample HP vc network layout refer my blog http://pibytes.wordpress.com/2012/07/10/hp-virtual-connect-vc-network-traffic-layout-2/