When you install Windows Server 2012, you can choose between Server Core Installation and Server with a GUI. The “Server with a GUI” option is the Windows Server 2012 equivalent of the Full installation option available in Windows Server 2008 R2. The “Server Core Installation” option reduces the space required on disk, the potential attack surface, and especially the servicing requirements, so we recommend that you choose the Server Core installation unless you have a particular need for the additional user interface elements and graphical management tools that are included in the “Server with a GUI” option. For this reason, the Server Core installation is now the default. Because you can freely switch between these options at any time later, one approach might be to initially install the Server with a GUI option, use the graphical tools to configure the server, and then later switch to the Server Core Installation option.

An intermediate state is possible where you start with a Server with a GUI installation and then remove Server Graphical Shell, resulting in a server that comprises the “Minimal Server Interface,” Microsoft Management Console (MMC), Server Manager, and a subset of Control Panel. See the “Minimal Server Interface” section of this document for more information.

In addition, after installation of either option is complete, you can completely remove the binary files for server roles and features that you do not need, thereby conserving disk space and reducing the attack surface still further. See the “Features on Demand” section of this document for more information.

A server in Minimal Server Interface mode is about 300 MB smaller than the same server in Server with a GUI mode. A server in Server Core mode is about 4 GB smaller than the same server in Server with a GUI mode. For the smallest possible installation footprint, start with a Server Core installation and then completely remove any server roles or features you do not need by using Features on Demand.

In Windows Server 2012, you can remove the Server Graphical Shell, resulting in the “Minimal Server Interface.” This is similar to a Server with a GUI installation, but Internet Explorer 10, Windows Explorer, the desktop, and the Start screen are not installed. Microsoft Management Console (MMC), Server Manager, and a subset of Control Panel are still present.

Starting with a Server with a GUI installation, you can convert to the Minimal Server Interface at any time using Server Manager.

Note
When you change any of these options, you will have to restart the server for the change to take effect.

 

See the table below for a summary of which selections to make in Server Manager (or cmdlets to use in Windows PowerShell) in order to get a given installation state:

In previous versions of Windows, even if a server role or feature was disabled, the binary files for it were still present on the disk, consuming space. In Windows Server 2012, not only can you disable a role or feature, but you can also completely remove its files, a state shown as “removed” in Server Manager or “disabled with payload removed” in Dism.exe. To reinstall a role or feature that been completely removed, you must have access to an installation source.

To completely remove a role or feature, use –Remove with the Uninstall-WindowsFeature cmdlet of Windows PowerShell. For example, to completely remove Windows Explorer, Internet Explorer, and dependent components, run the following Windows PowerShell command:

Uninstall-WindowsFeature Server-Gui-Shell -Remove

To install a role or feature that has been completely removed, use the Windows PowerShell –Source option of the Install-WindowsFeature Server Manager cmdlet. The –Source option specifies a path to a WIM image and the index number of the image. If you do not specify a –Source option, Windows will use Windows Update by default. Offline VHDs cannot be used as a source for installing roles or features which have been completely removed.

Only component sources from the exact same version of Windows are supported. For example, a component source derived from the Windows Server Developer Preview is not a valid installation source for a server running Windows Server 2012.

To install a removed role or feature using a WIM image, use the steps and Windows PowerShell cmdlets:

1. Run Get-windowsimage –imagepath <path to wim>\install.wim, and make note of the index of the Windows Server 2012 image.
    
2. Install-WindowsFeature <featurename> -Source wim:<path>:<index>, where:
   
   Featurename is the name of the role or feature from Get-WindowsFeature
   
   Path is the path to the WIM mount point
   
   Index is the index of the server image from Step 1.
    

For example: Install-WindowsFeature <featurename> -Source wim:d:\sources\install.wim:4

You can also specify a source for servers that are domain members using Group Policy. Navigate to Computer Configuration > Administrative Templates > System > “Specify settings for optional component installation and component repair”

Note

Permissions might affect the system’s ability to access Windows features for installation over a network. The Trusted Installer process runs within the machine account. If you encounter network access issues, try issuing a net use command (for example, net use * \\path\to\network or the cmdlet New-PSDrive -Name Z -PSProvider Filesystem -Root "\\path\to\network) to mount the network source and then copy the source locally. Then use the local copy as the installation source.

 

These examples give you an idea of how you can choose the installation option that might be most appropriate for your deployment needs:

• Server Core installations require approximately 4 GB less space than a Server with a GUI installation. By using Server Core installations on virtual machines, you can achieve a significant space savings by not having to store the GUI files on the virtual machine’s disk.
   
• Servers often have comparatively large amounts of memory and complex disk arrays, both of which can take a significant amount of time to initialize at startup. Because Server Core installations minimize the number of restarts required for updates, the frequency at which disk arrays and memory must be re-initialized is reduced.
   
• Certain server applications have dependencies on certain Windows services, libraries, applications, and files that are not available in Server Core installations, but the administrator wants to take advantage of the reduced need for updating typical of Server Core installations. The Minimal Server Interface offers additional compatibility while still maintaining a reduced system footprint (though to a lesser extent than a Server Core installation). 
   
• Features on Demand can be used to reduce the footprint for your virtual machine deployments by removing roles and features that will never be deployed in your virtual machines. Depending on the roles and features used in your virtual machines, it is possible to reduce the size by over 1 GB.
   

This table summarizes which features are available locally depending on which installation option you choose.