Windows Server - Understanding Server Manager, Roles and Features

What is Server Manager?

Server Manager is the primary graphical tool used to manage both local and remote servers. With Server Manager you can create groups of servers. This enables you to perform administrative tasks quickly across multiple servers that perform the same role, or are members of the same group.  Additionally, Server Manager provides access to many administrative tools.

What are Windows Server Roles?
Windows Server 2012 roles describe a server's primary function. For example, a server role might be deploying files, accessing web content, or centrally printing a file. You can select to install one or more roles on a Windows Server 2012 environment.
The Add Roles and Features Wizard and the Remove Roles and Features Wizard in Server Manager modifies the roles that are installed.

Note: When you deploy a role, Windows Server 2012 automatically configures aspects of the server’s configuration, such as firewall settings, to support the role. Windows Server 2012 also automatically and simultaneously deploys role dependencies. For example, when you install the Windows Server Update Services (WSUS) role, the Web Server (IIS) role components that are required to support the WSUS role are automatically installed.

What are Windows Server Features?
Windows Server 2012 features are independent components that often support role services or support the server directly. For example, Windows Server Backup is a feature because it only provides backup support for the local server. It is not a resource that other servers on the network can use.
The Add Roles and Features Wizard and the Remove Roles and Features Wizard in Server Manager modifies the roles that are installed.