In the hubbub over Microsoft's modifications to Windows 8, you may have missed the fact that the Windows Server 2012 R2 Preview is now available. In this release, Microsoft expands upon its vision of the "cloud OS" and makes several improvements to Hyper-V virtualization.
If you haven't tried Server 2012 yet, it's a platform intended to divorce applications from hardware, integrating virtualization and cloud computing in order to maximize resources and efficiency (see Welcome to the Server 2012 Cloud). It received rave reviews at launch last fall, not only for its future potential, but also for the reliability and usability of built-in tools.
Now R2 is in preview and is already making significant improvements, especially in the area of virtualization. A Microsoft e-book written by Mitch Tulloch explains all of the updates in detail, but here we outline the major changes.
Generation 2 VMs
Windows Server 2012 R2 supports two types of virtual machines: Generation 1 and Generation 2. This allows VMs to be created in either the Hyper-V BIOS or Hyper-V Unified Extensible Firmware Interface (UEFI) BIOS. The UEFI-based architecture with its Generation 2 VMs provides better security, flexibility, and speed.
Automatic VM activation
When a new virtual machine, with Windows Server 2012 R2 installed as the guest operating system, boots up for the first time on a Hyper-V host running a datacenter edition of Windows Server, the new virtual machine checks to see whether the host machine has been activated. If it has, the VM automatically activates itself as well, saving system administrators time and effort.
Windows Server 2012 R2 allows administrators to use Hyper-V Manager to export a complete copy of a running VM, or to export any snapshot of a running VM. In the past, this required downtime. It's also possible to clone a running VM and export snapshots while a VM is running.
Virtual disk storage improvements
Windows Server 2012 R2 allows administrators to share virtual hard disks (VHDX) as storage for clustered applications. This eliminates the need for costly storage area networking hardware high availability environments. R2 also provides online resizing, which is the ability to increase or decrease the size of virtual hard disk attached to a VM while the VM remains online. In addition, new storage quality of service (QoS) capabilities in R2 allow administrators to specify minimum and maximum loads for each virtual hard disk, helping to ensure that the throughput of one doesn't have an impact on that of another.
Hyper-V Replica gets flexible
Hyper-V Replica provides replication of virtual machines between two Hyper-V hosts to create a backup copy in case of emergency. In Server 2012 R2, customers can set the frequency of replication, making it more or less frequent than the previous standard setting of every five minutes. They also have the option to replicate VMs to a third disaster recovery server, to Windows Azure, or to another cloud provider.
Linux support improves
Hyper-V has supported Linux in the past to some degree, but with Server 2012 it is trying very hard to make it easy to run Linux on Windows. Improvements in R2 include supporting Dynamic Memory for Linux VMs, online VHDX capabilities, and online backup to a Microsoft or third-party backup solution.
Do these features make you interested in Server 2012 R2? What else would you like to see addressed? Read Microsoft's e-book for more information, and let's discuss in the comments.