vSphere 5 vRAM Considerations

July 12th VMware officially announced vSphere 5 and all of its awesome new features. One of these “features” is called vRam Entitlements. Basically what this “feature” does is limit the amount of physical RAM that you can put in your servers.

These days with servers that can hold hundred of gigabytes of RAM VMware probably feels that they are getting screwed over and losing a ot of cash on all those extra CPU licenses that your not buying anymore. When you stop and think about it, its really obvious from the bean counter side of things.

If my workload requires 128GB of RAM (not count the extra RAM for failover or overhead), and I only need the features of the “Standard” licensing. (Same scenario applies to Enterprise vs Enterprise Plus… just different numbers) I have a couple choices:

  • Buy four servers with 32GB of ram in each server (totaling 128GB of RAM and 8 CPU sockets)
  • Buy two servers with 64GB of RAM in each server (totaling 128GB of RAM and 4 CPU sockets)

So from the VMware licensing side of things (in the vSphere 4.x days) the first option would give VMware a check for $995 x 4 (4 CPU sockets x $995 a license) so $3980 (not including SnS), and the second option (in the vSphere 4.x days) would get VMware a check for $995 * 8 (because of the 8 CPU sockets), totaling $7960.

So from your point of view (as a customer) you would probably much rather right the check for $4k and invest the difference in those bigger RAM chips. Well with vSphere 5 and the vRAM Entitlement you can no longer use Standard licenses for that second option…. because we are only allowed to have 24GB of RAM / CPU license now. So they are forcing you to step up to Enterprise licensing to allow for that 32GB of RAM / CPU license… meaning your check for that smaller server is now going to be $2875 * 4 … getting VMware a check for $11500 instead of $3980. (Alternatively you could buy more VMware Standard licenses and add them to vCenter)

Clearly this is protecting them from peopling who are buying MONSTER servers with hundreds of GB of RAM in them. So if you are planning a project here is what you need to know:

A typical DL380/360 – 2 CPU socket server can now only hold 48GB of RAM if you want to use ANY version of vSphere 5 that is lower then Enterprise licensing. HOWEVER if you buy vSphere 4.1 Advanced NOW and have SnS when vSphere 5 becomes available you are grandfathered in for vSphere 5 Enterprise! Which gives you the ability to go for 64GB of RAM per DL380/360.

Bottom line if your are planning a project with servers with more then 48GB of RAM per server…. BUY YOUR LICENSING NOW BEFORE vSPHERE 5 is GA.

 

Side Note:

It looks like vRAM is technically a pool limit…. not a hard limit based on physical Socket but more likely based on each CPU license. So you do have one other option and that is to buy more CPU licenses then you really need. For example with Essentials and Essentials Plus you are now limited to 24GB of vRAM / CPU license. You get 6 CPU license with that bundle so you get the vRAM entitlement of 144GB total…. If you only have two physical hosts you could then have 72GB of RAM per host instead of 48GB…. but total you still only get 144GB so if you added a third host later… you would have to take RAM out of host 1 and 2 and put it in host 3.

Also vRAM is based on the amount of memory actually allocated to the VM… so if you give a virtual machine 8GB… that 8GB counts against your vRAM number…. it does not however include the 400MB of overhead or the amount of memory the hypervisor is using etc. So you actually can put as much physical RAM as you want in the box… but if your vRAM entitlement is 144GB … then you can only allocate 144GB or VM’s the other RAM would just sit idle or be used for overhead…. most would just sit idle though.

I will make additional posts as the smoke clears.

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8 Responses to "vSphere 5 vRAM Considerations"

  1. I can understand VMware’s position, and I’m sure there will be winners as well as losers from an end-user perspective.

    What worries me, as a potential Essentials customer, is that whilst 144GB sounds a lot at the moment, in a couple of years time my six year old son’s new laptop will probably come installed with more RAM than that.

    So they’re not screwing me now, but will they screw me further down the line?

  2. One note, the Pool Limit for vRAM is across the entire vCenter (Linked Mode counts too) and distributes the vRAM pool to all servers controlled by the vCenter. So, a Server with 256GB of RAM can still be covered with 2 CPU licenses if the entire pool has enough vRAM capacity across the Datacenter to accommodate the powered on VM’s.

    In addition, everyone overlooks the fact that you can now have unlimited RAM and no CORE/CPU restrictions in your server even with Standard Edition. I needed Enterprise Plus if I wanted 256GB+ or more than 8Cores/CPU previously.

  3. Great Points! I tried to express that but I dont deal with Linked mode too much, and the SMB target audience I normally shoot for wont see it too much either so that is why I was just saying the entitlement was “cluster wide” because normally the projects I’m on only have one DC and one cluster.

    Thanks again for the comment!
    JP

  4. Hey Justin,

    Love the blog – keep up the quality posts!

    In your example about buying advanced now and getting enterprise entitlement later…

    “A typical DL380/360 – 2 CPU socket server can now only hold 48GB of RAM if you want to use ANY version of vSphere 5 that is lower then Enterprise licensing. HOWEVER if you buy vSphere 4.1 Advanced NOW and have SnS when vSphere 5 becomes available you are grandfathered in for vSphere 5 Enterprise! Which gives you the ability to go for 128GB of RAM per DL380/360.”

    A 2 socket server licensed with 2x enterprise licenses in vSphere 5 will entitle you to 64GB of vRAM allocation (32GB per processor license), not 128GB, so it doesn’t make a whole lot of sense to put more than 64GB of memory in each 2 socket server licensed for enterprise.

    Will

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