Receiving slightly less attention than its client brother, Windows Server 2008 R2 -- also known as Windows 7 Server -- made its pre-release debut a couple of weeks ago. But with this new incremental release, there are quite a few changes under the hood that may make this something you should watch. In this piece, I'll look at some general facts about the release and then drill into a few key improvements and new features.
Windows Server 2008 R2 will be the first mainstream Windows Server release to be 64-bit only, meaning that older servers that don't support one of the families of 64-bit processor extensions won't be able to be upgraded. They will, however, be able to run Windows Server 2008, and some of the enhancements in R2 will work fine in environments with servers running plain-vanilla Windows Server 2008 as well. This release also marks the second time the client release (in this case, Windows 7) and the server release of the Windows product have been developed jointly, resulting in tighter integration, better compatibility and an extensive amount of testing.
One of the big concerns around Windows Server 2008 R2 may be the changes that were made to the operating system kernel that will allow Windows to support up to 256 processors. Microsoft expects that compatibility with Windows Server 2008 will be nearly identical to the level of compatibility that existed between Windows Server 2003 and Windows Server 2003 R2. But because these low-level changes were made, Microsoft can no longer guarantee 100% application compatibility in this release,like it could between Windows Server 2003 and Windows Server 2003 R2. When making deployment plans, be sure to account for this testing time.
Key feature highlights
Some of the key nice bits included in Windows Server 2008 R2 at the M3 milestone, which was the build given to attendees of the Professional Developers Conference just a couple of weeks ago:
Live migration: Live Migration is, of course, the Microsoft response to VMware 's popular VMotion technology that allows you to move a virtual machine from one physical host to another with no downtime -- a seamless transition from the perspective of your users. While the existing release of Hyper-V supports quick migration, there were a few seconds of downtime associated with the move and that has been removed. This is what many users have been waiting for before settling on Hyper-V for their virtualization solution, and now Hyper-V offers feature parity with VMware's enterprise solutions in many scenarios.