It’s been just under a year since Microsoft released Windows Server 2012. Touted as an operating system built for the cloud, Server 2012 promised some significant improvements to storage, networking, and virtualization services. It tried to strike a balance between the complex and varied needs of its data center customers and the simplicity smaller organizations needed to keep down costs.
Now Microsoft has unveiled the preview of Windows Server 2012 R2. It’s not just a “service pack” of bug fixes for last September’s release—this is a full update with a raft of further improvements targeted at further knocking down the walls between on-premises servers and private and public clouds. Some of those changes fine-tune the balance between simplicity of management and the enterprise power Microsoft was going for. They continue to enhance the server platform’s suitability both as a component of a cloud-computing environment and as an on-ramp to cloud services for small and mid-sized organizations.
Microsoft is also previewing updates to its system management platform System Center 2012 R2 and to Windows Server 2012 Essentials, the “easy deploy” successor to Microsoft’s Windows Small Business Server. Among other things, System Center 2012 R2 and Windows Server 2012 together improve Microsoft’s support for Linux virtual hosts within a Microsoft-managed environment. And the new version of Server Essentials has bigger ambitions than just the server under your desk—it’s been beefed up to appeal to mid-sized businesses and optimized further for deployment in the cloud. Now service providers can offer hosted Windows domains to their customers and give them simple-to-use administrative tools that can be remotely accessed.
All of these pieces fit into what Microsoft has called the “Cloud OS,” an over-arching architecture that will connect on-site servers at small and medium businesses and servers in corporate data centers with cloud-based services. It blurs the boundaries between what’s yours, what’s your service providers’, and what runs in Microsoft’s software-as-a-service and cloud infrastructure services. So most of the changes to the internals in R2 are focused on enhancements to storage, networking, and virtualization. But there are a few visible changes that will appeal to organizations that aren’t necessarily looking to scale out a cloud on their own.
We’ve been testing Windows Server 2012 R2 Preview for the past few weeks in tandem with Microsoft’s expanding cloud service portfolio and a collection of desktop and mobile clients. (We took a brief look at the Windows Desktop Experience in R2 just as the preview was released.) For this first look at what’s coming in 2012 R2, we’ll focus on some of the features that have the broadest appeal and will have the most direct impact on users.
Hyper-V, the next generation
The Hyper-V hypervisor is at the heart of Microsoft’s push for relevance in the “cloud”—whether in a hosting company’s rack space, a private corporate data center, or a server under your desk. There were some major improvements to Hyper-V in the last release of the platform. And Microsoft offered up a free standalone version called Hyper-V Server 2012, which it released at the time of Windows Server 2012’s launch (as a sort of loss-leader to draw attention to the platform and away from VMware). But despite the really great licensing deal and the general improvements in Hyper-V, there were still a few gaps in functionality that left it out of contention for many virtualization applications.
There are some significant changes in R2 that help narrow (but perhaps not quite close) those gaps. Replication between Hyper-V servers has been beefed up in terms of speed, frequency, and expanded disaster recovery options. There’s also the ability to now set storage quality of service levels for specific VMs to guarantee them specific levels of disk I/O throughput. This way you can give servers supporting databases priority over Web servers in getting disk I/O.
You don’t need to be running clustered virtual machines with big databases to get benefits from some of the new features in Hyper-V, however. Some of the most long sought-after improvements coming in R2’s Hyper-V are in its support for Linux virtual machines. Linux has run on Hyper-V since 2009, but it’s been something of a second-class virtual citizen in Hyper-V land. Yes, it ran. But even in Server 2012, which made big strides with Hyper-V, there wasn’t support for remote replication of Linux VMs for disaster recovery.
R2 adds that critical feature, plus a few others that were restricted to Windows VMs in previous releases. These include things like dynamic memory and dynamic resizing of the virtual drives associated with Linux VMs. Previously memory and disk resources for a Linux server were pretty much stuck at whatever you dialed in at configuration. In R2’s Hyper-V, you can reclaim un-partitioned space from a virtual SCSI drive or grow any VHD or VHDX virtual SCSI drive dynamically without shutting down the virtual machine. And in R2, enterprise backup tools that are built to work with Hyper-V will be able to directly back up Linux VMs just as they’ve been able to do with Windows VMs in the past.

Full Story: Windows Server 2012 R2 Preview: Your cloud on-ramp is under construction | Ars Technica.