A version of Windows for servers based on Windows 8.1 and a significant update to Windows Server 2012. Questions about administering Windows Server systems that are specific to a business environment are off topic for Super User; please consider asking on Server Fault instead if your question is on topic there.
At the heart of the Microsoft Cloud OS vision, Windows Server 2012 R2 brings Microsoft’s experience delivering global-scale cloud services into your infrastructure with new features and enhancements in virtualization, management, storage, networking, virtual desktop infrastructure, access and information protection, the web and application platform, and more.
