Yesterday VMware announced the release of vSphere 5. Some great new features were announced (Storage DRS for one). But included in the announcement was a change to their licensing model. Under vSphere 5, VMware editions are licensed on a per CPU socket (not core) basis and pooled virtual RAM (vRAM). I applaud any changes that bring licensing models closer to the way public/private cloud chargeback models work. But digging into the licensing model revealed some nasty surprises. At the company I work for, the change effectively increases our VMware licensing costs by 33%.
Here's how it shakes down for us. Our standard VMware ESX is a blade server consisting of 2 CPUs with 6 cores each (12 cores total), and 128GB RAM. Most of our applications, like many other companies, are memory intensive and not CPU intensive. Our standard is to license each blade with VMware vSphere Enterprise Plus edition.
Under the new licensing model, purchasing a 1 socket license of Enterprise Plus entitles to you 48GB of vRAM to allocate to VMs. VMware makes no mention of being able to purchase vRAM entitlements without purchasing the socket license. So in our scenario, we'll have to purchase a 3 socket Enterprise Plus license for our 2 socket blade server in order to use all 128GB of physical RAM.
3 socket license entitles us to 144GB RAM (3 x 48GB)
2 socket license entitles us to 96 GB RAM (2 x 48GB)
Further with the 3 socket license, now we are over entitled on the vRAM, meaning we essentially licensed more vRAM (144GB) than we have physically installed on the blade (128GB). If we had gone with the 2 socket license, we would have under licensed the vRAM (96GB) verses the physical RAM (128GB) and wasted installed RAM.
Now VMware counters that vRAM entitlments are pooled across a cluster (provided all cluster nodes are running the same edition of vSphere e.g. Enterprise Plus). Yes, I like that but it still doesn't solve my problem of this low 48GB vRAM entitlement with Enterprise Plus.
So based on our current blade configuration our licensing costs have increased by 33%. Multiply that across a 36 blade VMware cluster, and the cost increase becomes very serious. Serious enough to have me revisit Gartner's 2011 Virtualization Magic quadrant and re-evaluate VMware as the virtualization platform for the organization. Alternatively, we'll have to reconsider our standard blade server configuration to find a more optimal balance between sockets and installed RAM.
To rub salt in the wound, as of Aug 12, VMware will no longer be selling vSphere 4.1 licenses, only vSphere 5. However, vSphere 5 licenses do come with downgrade rights to vSphere 4.
A quick check on Twitter (#vmwlicensing) shows many VMware users are up in arms over this change. Let's hope by the time VMworld 2011 happens, VMware has reconsidered vRAM entitlement thresholds, or perhaps offers vRAM to be purchased/licensed a la carte.
You can read about the new vSphere 5 licensing model here.
