is the pooling of vRAM entitlements limited to a single vCenter instance, I mean - if you have multiple vCenter instances, does that mean that you also have multiple vRAM pools?
Or is the licensing component in vSphere 5 now able to be used by multiple vCenter instances?
What about linked mode?
This might relax people that maybe have a legacy farm with 2- to 4-core-CPUs and not-so-much-RAM per CPU on the one side (with a plenty of unused vRAM entitlements), and another modern farm with 6- to 12-core CPUs and 128GB+ RAM per CPU (with the desperate need for more vRAM entitlements) on the other side ...
The vRAM pool can span across multiple vCenter that in link mode.
According to the lic pdf "As long as the total consumed
Yes, but think of a situation where you don't want to use linked mode, but have several separated installations - maybe in a multi-national enterprise - that are also managed by different entities and people...
In such a situation it would be good to either
a) have a globally usable licensing service with CPU and vRAM entitlement pooled all over the enterprise, or at least:
b) to be legally entitled to over-subscribe vRAM-entitlements in one environment if you under-utilize the pool of another environment to the same amount (Practically this can easily be possible, because vRAM pool entitlements are not technically enforced).
Probably, only a VMware guy can answer this question, but it's an important one for large enterprises.