There have been gobs of reactions to VMware’s new license model that was announced last week, and the vast majority of it was negative. I will admit that I took part in some of the initial back lash. We sysadmins don’t like change, especially when we’ve engineered systems to maximize a certain licensing model and then that model changes. But then I started to think it’s possible likely that I’m overreacting. Maybe it won’t have any effect on us. So I started doing the math. Licenses are still purchase by the CPU, at minimum one for each socket in your system, with each license having a vRAM Entitlement. For reference, one of the best license summaries I’ve found is on Alan Renouf’s blog http://www.virtu-al.net. (the following is borrowed from his blog post http://www.virtu-al.net/2011/07/14/vsphere-5-license-entitlements/)
License Type Essentials Essentials Plus Standard Enterprise Enterprise Plus vRAM Entitlement per license 24GB 24GB 24GB 32GB 48GB
We currently have Enterprise Licensing with the following specs:
5 hosts – each with 2 CPU and a total of 256GB physical RAM (pRAM here on out)
70 Virtual Machines wth a total of 140GB Virtual RAM allocated (vRAM). But we also have about 20 powered off virtual machines for test/dev with an average of 4GB RAM each. So worst case scenario for vRAM is 220GB
The Math
10 Licensed CPUs @ 32GB Entitlement per CPU = 320GB of RAM Entitlements.
So as you can see, at the moment, we’re totally fine. Primarily because we have too many hosts, which I plan to fix with eliminating 2 hosts (pRAM is much cheaper these days than when we started building our cluster, which allows for greater consolidation). This works out like so:
6 Licensed CPUs @ 32GB Entitlement per CPU = 192GB of RAM Entitlements
So I’ll still have 52GB vRAM overhead, but will have to careful with how many test/dev servers we turn on at the same time. I’m just glad there isn’t a ‘hard stop’ when you hit your entitlement limit. I’m just not excited to one day tell my CIO that I have to purchase more CPU licenses than we have CPUs.
Not All Bad
I understand where VMware was going with this new model. One of the major tenets of the Cloud is the ‘pay for what you need/use, not what you don’t’. VMware’s philosophy is now a ‘license only how much vRAM you need, not your pRAM’. When I lamented that new virtual machines are becoming more of a business decision, this isn’t all bad. VM sprawl is very much real. Especially with RAM and CPU speeds and feeds exploding for such a minimal cost increase, we vAdmins have to think less and less about what resources our machines actually need. New Windows Server 2008 R2? Ah, just go ahead and give it 8GB off the bat. Why not?
I think it will help admins and users think critically about the resources they allocate to machines and force people to ‘right-size’ them. Really, we’ll be thankful 5-10 years down the road when if we migrate virtualization platforms. (oh no he didn’t)
For those that are adopting or have adopted a charge back model, this will make it much easier to manage and explain the costs of your tiered environment. You want a big beefy server with tons of RAM? Groovy. That’ll be $90/1GB RAM/year. But you can have all CPU you need.
Left Over Beef
- VMware that says they removed “two physical constraints (core and physical RAM)”, but they introduced a virtual constraint and I never had either of those 2 previous ones.
- The 8GB vRAM limit on free ESXi might be a home/test lab buster. Aren’t all the other restrictions enough?
- I think VMware could do lot by increasing the entitlement just a bit: 48GB for Enterprise, 64GB or 96GB for Enterprise+ would silence a lot of critics (but also cut into their profit margins)
But, these are just my thoughts as a sysadmin in an SMB shop. There doesn’t seem to be a huge impact us, yet. Oh, did I mention we’re in the beginning phases of a DR site? Yeah, this will influence some discussions there now.