Understanding the various editions available is vital when you decide to purchase Windows Server 2012. You need to have a basic understanding of the features and limitations in each edition in order to make a well-informed decision that best suits your environment. In this article I will attempt to list some of the elements you need to consider before choosing which edition is most appropriate for your case.
In Windows Server 2012, there are four editions: Foundation, Essentials, Standard, and Datacenter. Don’t let the naming deceive you. While the Foundation and Datacenter editions map directly to the Foundation and Datacenter editions in Windows Server 2008, the Essentials and Standard editions do not. The Essentials edition in 2012 is equivalent to the Standard and Web editions in 2008, while the Standard edition in 2012 maps to the Enterprise edition in 2008. That being said, it should be clear what is the most likely edition you want to choose when it comes to upgrading from your Windows Server 2008 environment. Please note that all Windows Server 2012 editions are 64-bit OS versions. There is no more support for 32-bit operating systems.
This edition is a scaled down edition of Windows Server 2012. It is intended for small businesses requiring simple file and print services and is limited to 15 users only. It can only be installed on a physical machine; the license for this edition will not allow for a virtual machine install. From an administrator perspective, although the server manager is available, unlike the other three editions it defaults to a dash board with simple tasks such as creating users. With these limitations, you should expect that it is the cheapest license of 2012 among the other editions.
If this server is used as a Routing and Remote Access Server (RRAS), that is either as a VPN for remote connection or as a router, then it supports up to 50 connections. Distributed File System is supported as a standalone DFS root; i.e. you will not benefit from replication and fault tolerance as this supports only one server. Likewise, this edition is limited to root only Active Directory Services domain controller on the root domain with no domain trusts. Similarly, Active Directory Certificate Services is limited to Certificate Authority only. This means that you will be able to create certificates but you will miss on managing certificates deployment. As it is a scaled down edition, you should expect that it does not support the Hyper-V role, nor it supports the Server Core.
This edition has the same set of features as the Foundation edition. However it supports 10 more users; in other words it is limited to 25 users only. Moreover it can be installed on either a physical machine or a virtual machine.
If used as a RRAS server, Essentials edition allows for a maximum of 250 connections. The limitations on DFS, Active Directory Services, CA, Server Core, and the Hyper-V role are exactly the same as those in the Foundation edition.
If you purchase this edition, you will be entitled for all the features of Windows Server 2012. The server license will entitle you for two virtual machine installations. Unlike the Foundation and Essentials editions, the concept of a limitation on the maximum number of users to support, no longer holds here. In the Standard, as well as Datacenter, edition you need to purchase Client Access Licenses for each user who needs to access services on the server. Therefore it allows for an unlimited amount of user access provided that CALs are purchased.
This edition allows for unlimited RRAS connections, unlimited DFS server setup, unlimited Active Directory Services setup, and unlimited Active Directory Certificate Services. It also allows for the Hyper-V role and provides the Server Core installation.
As in the Standard edition, the Datacenter edition provides the full set of features. However, you are not limited to a number of virtual machine installations; this edition supports an unlimited number of virtual instances on the same physical server. You need to know, though, that this edition is not available through retail channels. You need to get it as part of an agreement with Microsoft.
Like the Standard edition, Datacenter allows for unlimited RRAS connections, unlimited DFS server setup, unlimited Active Directory Services setup, and unlimited Active Directory Certificate Services. It also allows for the Hyper-V role and provides the Server Core installation.
Other Licensing Considerations
RAM: Foundation edition supports maximum 32 GB of RAM. Essentials edition supports 64 GB of RAM. Standard and Datacenter editions support up to 4 TB of RAM.
Processor Limits: Foundation license supports a maximum of 1 CPU on a physical machine only. Essentials can be installed on either a physical machine or a virtual machine and supports a maximum of 2 CPUs regardless of how many licenses you have. The Standard and Datacenter editions are licensed for a maximum of 2 CPUs per license. This means that if you installed Windows 2012 Standard or Datacenter on a physical machine with x number of CPUs, you will need to purchase x/2 number of licenses. For instance, if you install the Standard or Datacenter on a machine with 8 CPUs, you will need 4 licenses from that edition. Provided that you have purchased the licenses covering the CPU requirements, Datacenter has no other licensing implications. This means that you can have as many virtual instances of Windows 2012 on that same physical server without the need to purchase any additional server licenses. However, this is not the case with Windows 2012 Standard. Even if you have covered the CPU licensing requirements, each Standard license will entitle you for two virtual machine instances only. If you need more virtual machines, you will need to purchase additional licenses.
Please note that the number of cores does not matter. Licensing is not based on the number of cores per CPU. So you can have as many cores as you wish per CPU without causing any additional licensing implications.