Virtual PC was nice for Windows power users. But for developers and sys admins testing against specific OS images and doing similar business-oriented tasks, Virtual Server 2005 is the only thing out of Redmond that might make us stray from VMware. Fortunately, after slipping a couple of ship dates, Microsoft released Virtual Server late last year to semi-enthusiastic hand clapping from its customers.
But Microsoft never rests on one software version for too long -- especially these days. Hey, there’s too much money to be made in upgrades. Most times, the first upgrade in any Microsoft product lifecycle is called "R2" (Release 2), and so it is for Virtual Server 2005, which had its R2 release announced a couple of weeks ago. And true to form, Microsoft isn’t kidding around, incorporating what it sees as the best of its competitors’ features with the power it has over the OS.
For Virtual Server 2005 R2, this means changes in several areas. The two that I like best are support for native x64 hosting and, especially, PXE boot support. Being able to do a pixie boot off a central Virtual Server is a huge plus for any of us in the test lab business, and it’s now going to get its own dedicated hardware in my lab.
Test lab folks will also like the fact that there’s now room for “guest” operating systems. Unfortunately, that means only Linux. That also means only Red Hat and Suse for now -- and "for now" really means next month, not later this month, when R2 is fully released. That’s quite a few modifiers, but the door is open, and Microsoft has said it’ll be pushing out specific support for more platforms in 2006.
You’ll also find higher-end upgrades, such as the ability to support the clustering of virtual machines across iSCSI and SANs. That means you can cluster two or three physical machines and run a whole bunch of hosts over that; but, far cooler, it means you can cluster a bunch of virtual machines together, whether or not they’re on the same physical box.
To make this easier, Microsoft had to upgrade its virtual machine migration capabilities. If you’re running a pile of servers, connected together to form a virtual hosting landscape, then that hardware must be updated, modified, and maintained over time. To keep virtual machines from going down during that time, Virtual Server now does machine migration from one host to the next at less than 10 seconds per 128MB (assuming a 1GbE iSCSI interconnect medium). Redmond picked 128MB here because the company now has documentation that shows folks how to strip down Windows XP Pro to fit into 128MB such that a few hundred VM instances of the OS won’t eat up too much hardware.
Another key feature down that alley is its capability to change virtual hard disks dynamically. Prior to R2, these disks were fixed. Now, they can grow as you load more apps on them and even alert administrators when a single disk gets too large. Redmond is still working on the capability for those same images to shrink as you remove applications.