There has been a lot of rant about the new licensing model of vSphere 5 (see my previous post), because for certain customers (specifically those with a very high RAM per CPU ratio which is more and more common with recent server hardware) will need to buy more vSphere 5 licenses to cover the vRAM usage as they had vSphere 4 licenses before.
Before you start complaining yourself check your environment now to find out how it will affect you. There are a number of PowerCLI scripts available now for doing this. I personally like LucD's the most, get it here: http://www.lucd.info/2011/07/13/query-vram/.
For my production environment it outputs the following:
vCenter : [MyVC-FQDN]
vRAMConfigured : 2732.2
vRAMUsed : 2624.8
vRAMEntitled : 6000
LicenseType : vSphere 4 Enterprise Plus
Note that the used vRAM is lower than the configured vRAM, because it only takes into account the total RAM of all running VMs (and I also have some that are powered off).
The current version of the script also counts the assigned licenses only. However, if you have spare licenses that are currently unassigned, they will also add up to vRAM entitlements once they are upgraded to vSphere 5 (I ask Luc to fix that, maybe there is a new version of his script soon).
Anyway, as you can see, I am lucky with the new licensing model and would (yet) have plenty of unused vRAM in my pool if I upgraded today.
Update: There is now an even better script available by Virtu-Al: It can also handle ESX versions earlier than 4.1, looks for unassigned licenses and has a nice HTML output:
It is referenced in an official VMware Blog post that tries to better explain the new licensing model and the motivation behind it.