Microsoft Per Core (with CAL) licensing rules
Summarize
Summary of Microsoft Per Core (with CAL) licensing rules
The Microsoft Per Core (with CAL) licensing metric is designed for licensing physical servers based on the total number of cores. This metric applies specifically to on-premises installations and does not extend to cloud environments.
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Key Features
- Standard Edition Licensing: Requires licensing for all physical cores on the server, with a minimum of 8 cores per processor and 16 cores per server. This allows installation on up to 2 VMs per server, with additional licensing required for extra VMs or software installations.
- Datacenter Edition Licensing: Similar core licensing rules apply, but it allows for unlimited VMs and software installations on each OSE, providing significant benefits for highly virtualized environments.
- Cluster Licensing: Each physical server in a cluster must be licensed for all VMs that can run on it, due to the potential for VM migration (v-motion). This makes Datacenter edition preferable for clusters due to its unlimited virtualization capabilities.
Key Outcomes
By understanding and applying these licensing rules, ServiceNow customers can ensure compliance and optimize their software asset management. Effective licensing can lead to cost savings and improved resource allocation in both standard and clustered server environments.
The Per Core (with CAL) license metric licenses physical servers. The number of licenses depends on the number of installs and operating system environments (OSE).
The licensing rules mentioned in this section are based on the assumption that you are using the Per Core (with CAL) license metric to license on-premises installations. These rules do not apply to cloud installations.
Licensing rules for non cluster physical servers (Standard edition)
To license a physical server with or without virtual machines (VMs), the number of rights equal to total number of cores on the physical machine need to be licensed.
- The minimum number of cores that need to be licensed per processor is eight. If the number of cores in a processor is less than right, assume the number of cores to be eight for licensing purpose.
- The minimum number of cores that need to be licensed per server is 16. If the number of cores in a server is less than 16, assume the number of cores to be 16 for licensing purpose.
- Licensing all the cores of the physical server according to the above rules allows the software to be installed on two VMs on the server (VMs with software installed are also called Operating System Environments or OSEs). For every extra pair of VMs having software installed, all the cores of the physical server need to be licensed again. This is also known as stacking of rights.
- Licensing all the cores of the physical server according to the above rules allows only one install of software on each OSE. For every extra install of software, all the cores of the physical server need to be licensed again.
- Software using Per Core (with CAL) license metric can only be licensed on the physical server which in turn licences the VMs automatically using the rules mentioned above. These licenses cannot be used to license the VMs directly by counting the number of cores on VMs.
- For every extra pair of VM, you need to license the physical server again, Standard licenses are usually used in Servers having low level of virtualization.
- Maximum cores per processor: 8
- Minimum cores per server: 16
- Maximum OSE per server: 2
- Maximum installs per OSE: 1
- a: # processors * actual cores per processor
- b: # processors * Minimum cores per processor (8)
- c: Minimum cores per server (16)
Licensing rules for non cluster physical servers (Datacenter edition)
To license a physical server with or without VMs, the number of rights equal to total number of cores on the physical machine need to be licensed.
- The minimum number of cores that need to be licensed per processor is eight. If the number of cores in a processor is less than eight, assume the number of cores to be eight for licensing purpose.
- The minimum number of cores that need to be licensed per server is 16. If the number of cores in a server is less than 16, assume the number of cores to be 16 for licensing purpose.
- Licensing all the cores of the physical server according to the above rules allows the software to be installed on unlimited number of VMs on the server (also known as unlimited virtualization benefit of DC edition)
- Licensing all the cores of the physical server with the rules above allows unlimited number of software installations on each OSE.
Licensing rules for physical servers part of a cluster
- When a server is part of a cluster, according to Microsoft, the Server needs to be licensed for all the VMs that can potentially live on the server at any point in time.
- Because of v-motion, any VM that is part of the cluster can potentially live on any host in the cluster at some point in time. As a result, according to Microsoft, each server needs to be licensed for all the VMs which are in the entire cluster.
- Apart from the impact of v-motion discussed above, the licensing rules for both Standard and DC editions are exactly same as in a non-cluster environment.
- Since each host in a cluster needs to be licensed for each VM that lives on the cluster, it is beneficial to use DC licenses for clusters, since DC edition provides unlimited virtualization benefits.
Allocations
For non-cluster machines, the allocations need to be made on the physical server. Allocation made to VMs get ignored.
For machines part of a cluster, the allocations need to be made to the cluster. You need to calculate number of rights consumed by each physical on the cluster, sum them up to calculate the number of rights required by the entire cluster and allocate that many rights to the cluster. Allocations made to physical servers or VMs in a clustered environment get ignored.