Virtualization saves money -- or so we're told. But how much does it save (if any) and how do we calculate the true costs? Paul Rubens discusses the thorny issue.
Working out how much virtualization is going to cost you has always been tricky, and it's certainly not getting any easier.
For example, VMware made a major change to the way it licenses vSphere -- part of its hybrid cloud infrastructure suite -- when it launched vSphere 5 recently, and it hasn't exactly made it straightforward to work out what the implications of that will be.
How does it work? Here goes: There's a per-CPU socket pricing element, as there was before, but there's also a vRAM entitlement that goes with that, and the amount of entitlement depends on the vSphere edition for which you buy a license. You can pool vRAM entitlements from licenses for any given edition of vSphere, and you dip into this pool to cover the configured memory of every powered-on virtual machine. Got that?
What happens if your pool runs out? In vSphere Essentials and Essentials plus you will not be able to power on a virtual machine if doing so would take you over your pooled vRAM entitlement, but in vSphere Standard, Enterprise and Enterprise Plus you will be able to, although you'll get a warning.
Read the rest about virtualization costs at ServerWatch.