veeam licensing question

You need to to license all hosts to be able to backup!

The same with VMware, you must licenses all hosts and processors in your Cluster or vSphere environment.

The only way would be to remove the hosts you do not want to license from vCenter Server, which then means you cannot back them up, or use them in that vCenter Server.

Subscription Licensing may be better for your budget, than perpetual licenses.

see here

https://www.veeam.com/faq.html

So they wouldnt be able to create a license combining the first group of hosts with the second?

No, you must be licensed for all processors in all hosts.

It's based on Managed Hosts in your vCenter Server Inventory.

so what happens if we go from the 8 hosts to 10 hosts? do they create a new license for the 10 hosts after we purchase the additional 4 sockets?

Thanks for the clarification on it.

Andrew's answer is not correct.
You don't have to license ALL hosts right now, only THOSE hosts you need/would like to protect NOW. That means that you can go with 8 sockets Ent+ license right now and add 8 more sockets later.

Note1: Even if you go with 8 sockets only, you're able to apply and invoke license for a host right from Veeam UI on the fly. It's very flexible in these terms.
Note2: Only hosts, which you plan to protect (meaning, they're hosting VMs that you'd like to back up) need to be licensed. DR or recovery or replication hosts (target for replication or recovery operations) don't consume any Veeam license.

and how does he protect the hosts, he does not have licenses for ?

not put any VMs on them ?

One option is to obtain a trial license which will last 30 days.  If you are able to order all 16 licenses at the beginning of next year this will suffice and Veeam is pretty good on extending their eval to another 30 days if required.  This would be an elegant solution to license all the systems and get everything tested.  Since it the end of the year you can probably squeeze out a better deal, must make sure it's valid into January if that's when you're looking to make the purchase

and how does he protect the hosts, he does not have licenses for? not put any VMs on them ?

Check initial question from the OP. He didn't ask about that

If he hosts are in a cluster using vmotion do i have to license all physical hosts if not all hosts are running vm's

While Paul's comment describes a good way to test things, I'd recommend to use this time before EOY, as it might be a price increase, starting from Jan 1. Just friendly warning.

if you have no VMs on hosts they do not need protecting or a license!

but why then have you go a cluster of 8 hosts? Have you licensed all these with VMware ?

So you could vMotion all your VMs to 4 hosts, license 4 hosts and back them up!

and turn off DRS. and make sure ALL hosts have capacity to run all your VMs.

But you've got a management procedure to move all VMs to 4 hosts, you could script it before backups start, or just script and Enter Maintenance Mode on four hosts, it will move all your VMs to remaining 4 in the cluster.

Run Backup Jobs, and then after backup job run the scripts, you can add pre and post scripts to Veeam Backup Jobs...

@Andrew Z.  - I realize the author didn't ask the question, the goal is provide options that may provide an elegant solution.  As Andrew H stated you can only backup VMs on the servers that are protected which may dictate the vmotion of VMs to get them backed up and reduce total resources in the cluster.