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peace420
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vSphere 5 New License Model and vMotion

Hi, I am still not clear for the vSphere 5 New License model.

How does vRAM entitlement limit guest machines?

Let's say if I purchase essential plus which supports 3 hosts with 2 processors each, and its vRAM entitlement is 32 GB for each CPU ( 3 Hosts x 2 CPU x 32 GB = 192 GB MAX).

This means I have 192 GB in vRAM pool?

So...if I have only one host, I can have 192 GB for the guests running on the single host?

If the max is 32 GB for each host, what is occured under the condition below?

1. purchase one essential plus

2. create 2 ESXi hosts to make HA

3. 5 guest machines run on one ESXi host, and their total of vRAM is almost 32GB

4. one guest machine runs on another ESXi host, and move the guest from the second ESXi to the first ESXi by vMotion.

5. vMotion will be failed because of limitaion of vRAM on the frist ESXi?

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jjkrueger
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Licensing is done on a per-CPU socket basis, meaning you must have one license per socket in each server you're licensing.

Each license instance also has a vRAM entitlement.  In the case of Essentials, that's 32GB/socket.

The Essentials Plus kit includes 6 CPU socket licenses and vCenter.

If you have a single host managed by that vCenter, all of the vRAM entitlement (192GB) would be available to that single host, as the vSphere Essentials 6 CPU socket licenses are pooled in vCenter, and only one host to allocate the entitled vRAM.

Remember that vRAM is simply the amount of memory assigned to virtual machines, not the amount of memory you can have installed in a host.

See the vSphere 5 Pricing and Packaging whitepaper for more detail (http://www.vmware.com/files/pdf/vsphere_pricing.pdf)  You may also want to double check everything with the account team, VAR or Integrator from whom you're planning on purchasing the licenses.

Now, if you have a vSphere High Availability cluster, you're not going to want to use 100% of your memory on each host anyway, as you'll want to keep resources reserved and available for a failover situation.  For 3 hosts, as an example and no memory overcommitment, you'll want to ensure that at least ~33% of your memory resources are unused in case a host fails.  In the case of , say, Essentials Plus, you'll have 192GB of vRAM entitlement available to your cluster, and with an evenly spread workload, that would mean 64GB of active vRAM on each host.  To compensate for HA resources, the hosts would likely be sized at a minimum of 96GB physical RAM each (64GB for the active VMs, and 32GB for the failover memory capacity) or more, depending on utilization tolerances.  That would mean purchasing 288GB of physical RAM for the 3 hosts, while only 192GB is licensed based on the vRAM entitlement.

If you only have 2 hosts in your cluster, you still have access to the 192GB vRAM entitlement from the Essentials Plus kit.  Obviously, the numbers will work out differently.  You could use 96GB of vRAM on each host, but at that point, you would need to purchase your hosts with at least 192GB of physical RAM each to accomodate a host failure (again, assuming no memory overcommitment on the hosts).

License pooling is predicated on having a vCenter server managing your licenses.

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AKostur
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If your one host has a whole bunch of real RAM in it, sure.  Actually there's a clause in the licencing that a single VM takes at most 96 GB vRAM.  So you could have 2 VMs at 192 GB each.

Note that vRAM is calculated across your entire cluster, not per machine.   So when you vMotion a machine from one host to another, the vRAM assignment hasn't changed.  You get a total of 192 GB across all three hosts.

peace420
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Thank you for the quick answer.

Let me make sure...

So, your are saying it is a matter of total number of CPU and vRAM within ESXi cluster.

This means I can have single host with 6 CPU + 192 vRAM, or two hosts with 3 CPU each + 96 vRAM each, or three hosts with 2 CPU each + 64 vRAM each by purchaseing the essential kit or essential plus?

I still concern the limitation...

VMware say that vRAM support per CPU... so, this means I can have a single ESXi host with 6 CPU + 192 vRAM but I can not have a single host with 1 CPU + 192 vRAM by the essential license becasue of the limitation?

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jjkrueger
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Licensing is done on a per-CPU socket basis, meaning you must have one license per socket in each server you're licensing.

Each license instance also has a vRAM entitlement.  In the case of Essentials, that's 32GB/socket.

The Essentials Plus kit includes 6 CPU socket licenses and vCenter.

If you have a single host managed by that vCenter, all of the vRAM entitlement (192GB) would be available to that single host, as the vSphere Essentials 6 CPU socket licenses are pooled in vCenter, and only one host to allocate the entitled vRAM.

Remember that vRAM is simply the amount of memory assigned to virtual machines, not the amount of memory you can have installed in a host.

See the vSphere 5 Pricing and Packaging whitepaper for more detail (http://www.vmware.com/files/pdf/vsphere_pricing.pdf)  You may also want to double check everything with the account team, VAR or Integrator from whom you're planning on purchasing the licenses.

Now, if you have a vSphere High Availability cluster, you're not going to want to use 100% of your memory on each host anyway, as you'll want to keep resources reserved and available for a failover situation.  For 3 hosts, as an example and no memory overcommitment, you'll want to ensure that at least ~33% of your memory resources are unused in case a host fails.  In the case of , say, Essentials Plus, you'll have 192GB of vRAM entitlement available to your cluster, and with an evenly spread workload, that would mean 64GB of active vRAM on each host.  To compensate for HA resources, the hosts would likely be sized at a minimum of 96GB physical RAM each (64GB for the active VMs, and 32GB for the failover memory capacity) or more, depending on utilization tolerances.  That would mean purchasing 288GB of physical RAM for the 3 hosts, while only 192GB is licensed based on the vRAM entitlement.

If you only have 2 hosts in your cluster, you still have access to the 192GB vRAM entitlement from the Essentials Plus kit.  Obviously, the numbers will work out differently.  You could use 96GB of vRAM on each host, but at that point, you would need to purchase your hosts with at least 192GB of physical RAM each to accomodate a host failure (again, assuming no memory overcommitment on the hosts).

License pooling is predicated on having a vCenter server managing your licenses.

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peace420
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Great Answer.

Thank you very much.

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