Some perspective on the ‘thickness’ of Windows Virtualization
Virtualization August 17th, 2007I wanted to blog some more on recent chats I had at TechEd, particularly with some confusion with Windows Server Virtualization (aka Viridian). There was a common misconception that Microsoft Virtualization was “very fat“. So in an attempt to compare ‘apples to oranges‘ I thought I’d put some numbers out there, and put a loose perspective on things.
Firstly Windows Virtualization is not the same as Virtual Server. Sure they both run Virtual Machines, but I’ll use the analogy of comparing SQL and Microsoft Access. …you can use your imagination to decide which is which :)
Anyway, at the moment we all know that Virtual Server is installed on top of Windows 2003. So your install footprint consumes ~2 Gb. Then your Virtual Machines, run on top Virtual Server. As per the diagram to your right. >
So lets fast forward a little bit. Windows 2008 CTP (aka Longhorn) has an install footprint of ~4.4 Gb. But we don’t need most of that install base to run Windows Virtualization.
So Windows 2008 can also be installed in a mode called ’Windows Server Core‘. Windows Core is a lean and mean install of Windows without any of the ’bells and whistles‘. Core has an install footprint of ~1.3 Gb. Then we need to add the hypervisor and Windows Virtualization role.
The hypervisor is super thin, and installed under Windows. Although I don’t have numbers I can publish at the moment, think Potato Crisp thin. Once the hypervisor is installed, your VMs essentially run beside your installation of Windows Core. again see the diagram above. ^
So an install footprint of Windows Core (1.3 Gb) is comparable to an install footprint of VMware ESX 3.0 which is about ~1.6 Gb. Now this is the install footprint. I haven’t gone into memory requirements or architecture, just the space consumed on the disk after an install.
If this has tantalized your tastebuds, and you’d like to know a little more about architectures check out Massimo Re Ferre’s post: A brief architecture overview of VMware ESX, XEN and MS Viridian or the WinHEC slidedeck Virtualization Stack, and Device Virtualization Architectures.
August 17th, 2007 at 3:01 am
Hi Dugie,
Nice post mate, I was stating to wonder what was actually meant by Viridian.
So effectively the Server Core will act as the Management HQ’s? and the Viridian slides underneath?
Is this available in the current Server Core beta’s? I guess not?
Thanks, I’ll keep an eye out for your next entry,
Dave
August 21st, 2007 at 4:50 pm
Dugie,
it might be worth to underline that this discussion is relevant in terms of disk space as you have mentioned. There is a confusion around for which in order to make Viridian and ESX look similarly you have to install Windows 2008 in “Core mode” as opposed to standard mode. This is not the case (performance-wise at least). What matters is how the architecture is layered out and not how big is the management instance. To make an example it would be like the time that it takes for a person to hit the street escaping from his hotel room: today with Virtual Server his room is at the 10th floor so it will take a while. Tomorrow with Viridian his room will be at the ground floor (well almost) so it will take very little to hit the street …. and it doesn’t matter if the hotel is 10, 20 or 30 floors tall.
Sure “Core mode” is a cool thing (less patches ? More secure ? etc etc) but people are looking at it in the wrong way (my opinion).
Massimo.