How many virtual machines can run on one physical machine?
Q. Can Windows Server Standard Edition really only run 2 Hyper-V virtual machines?A. No. Standard Edition can run just as many virtual machines as Datacenter Edition.I see and field this particular question quite frequently. A misunderstanding of licensing terminology and a lot of tribal knowledge has created an image of an artificial limitation with standard edition. The two editions have licensing differences. Their Hyper-V related functional differences: Show
Otherwise, the two editions share functionality. The True LimitationThe correct statement behind the misconception: a physical host with the minimum Windows Standard Edition license can operate two virtualized instances of Windows Server Standard Edition, as long as the physically-installed instance only operates the virtual machines. That’s a lot to say. But, anything less does not tell the complete story. Despite that, people try anyway. Unfortunately, they shorten it all the way down to, “you can only run two virtual machines,” which is not true. Virtual Machines Versus InstancesFirst part: a “virtual machine” and an “operating system instance” are not the same thing. When you use Hyper-V Manager or Failover Cluster Manager or PowerShell to create a new virtual machine, that’s a VM. That empty, non-functional thing that you just built. Hyper-V has a hard limit of 1,024 running virtual machines. I have no idea how many total VMs it will allow. Realistically, you will run out of hardware resources long before you hit any of the stated limits. Up to this point, everything applies equally to Windows Server Standard Edition and Windows Server Datacenter Edition (and Hyper-V Server, as well). The previous paragraph refers to functional limits. The misstatement that got us here sources from licensing limits. Licenses are legal things. You give money to Microsoft, they allow you to run their product. For this discussion, their operating system products concern us. The licenses in question allow us to run instances of Windows Server. Each distinct, active Windows kernel requires sufficient licensing. Explaining the “Two”The “two” is the most truthful part of the misconception. One Windows Server Standard Edition license pack allows for two virtualized instances of Windows Server. You need a certain number of license packs to reach a minimum level (see our eBook on the subject for more information). As a quick synopsis, the minimum license purchase applies to a single host and grants:
This does not explain everything — only enough to get through this article. Read the linked eBook for more details. Consult your license reseller. Insufficient licensing can cost you a great deal in fines. Take this seriously and talk to trained counsel.  What if I Need More Than Two Virtual Machines on Windows Server Standard Edition?If you need to run three or more virtual instances of Windows Server, then you buy more licenses for the host. Each time you satisfy the licensing requirements, you have the legal right to run another two Windows Server Standard instances. Due to the per-core licensing model introduced with Windows Server 2016, the minimums vary based on the total number of cores in a system. See the previously-linked eBook for more information. What About Other Operating Systems?If you need to run Linux or BSD instances, then you run them (some distributions do have paid licensing requirements; the distribution manufacturer makes the rules). Linux and BSD instances do not count against the Windows Server instances in any way. If you need to run instances of desktop Windows, then you need one Windows license per instance at the very least. I do not like to discuss licensing desktop Windows as it has complications and nuances. Definitely consult a licensing expert about those situations. In any case, the two virtualized instances granted by a Windows Server Standard license can only apply to Windows Server Standard. What About Datacenter Edition?Mostly, people choose Datacenter Edition for the features. If you need Storage Spaces Direct, then only Datacenter Edition can help you. However, Datacenter Edition allows for an unlimited number of running Windows Server instances. If you run enough on a single host, then the cost for Windows Server Standard eventually meets or exceeds the cost of Datacenter Edition. The exact point depends on the discounts you qualify for. You can expect to break even somewhere around ten to twelve virtual instances. What About Failover Clustering?Both Standard and Datacenter Edition can participate as full members in a failover cluster. Each physical host must have sufficient licenses to operate the maximum number of virtual machines it might ever run simultaneously. Consult with your license reseller for more information. Windows Server BackupIf you run or manage virtual environments that have one or more physical machines or legacy servers that have not been virtualised you can now use Altaro Physical Server Backup to protect these physical machines and keep them safe. Altaro Physical Server Backup is a windows server backup freeware solution created to satisfy this need, with the added bonus that it’s free. Back up the physical servers on your network through this P2V solution and benefit from a fast and easy recovery should they be impacted by a disaster. Download Altaro Physical Server Backup How many VMs can I run on a physical server?Nowadays, almost all servers come with two or four cores per physical CPU. A good rule of thumb is that four single CPU VMs can be supported per CPU core. This can vary by as much as 1-2 per core, and up to 8-10 per core based on the average CPU utilisation of applications running on VMs.
Can we run multiple VMs on a single physical machine?Using virtualization software, you can run multiple operating systems on one physical machine. The technology is now mainstream enough that it is a built-in feature in Windows 7 Professional (and above) and in Windows Server 2008 R2.
How many virtual machines can be run on a single host machine?Max 100 VMs per Host. If the number of Hosts exceeds 8 in a cluster, the limit of VMs per host is 40.
Can you run multiple virtual machines at once?The answer is YES. You can run multiple virtual machines simultaneously on a single host, and the virtual machines can appear as separate windowed applications or display in the full screen. You need a PC or Server with enough CPU cores, memory and disk to run your multiple VMs.
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