Kevin Remde's IT Pro Weblog
There’s a theory that a Shark needs to keep moving, or else it will die.
“Is that really true?”
Do I look like Jacques Cousteau? I don’t know. You look it up. But I think the same can be said for virtual machines.
Stop interrupting me. In your datacenter, no machine in production should ever be unavailable. Period. It’s there for a reason, whether or not it is running on physical hardware or as a virtual machine. Just because it’s virtual doesn’t make it any less important. Downtime (death) is not an option.
But the realities of hardware and operating systems are still such that sometimes you need to update/upgrade/shift/repurpose/etc. A benefit of virtualization is that we can adjust and move virtualized servers and their storage to different hardware when these transitions (planned or not) are taking place. So.. VMs move. And they move. And they must never die.
Both Microsoft and VMware have capabilities that allow you to move running virtual machines and their storage from one place to another with no downtime. VMware calls it vMotion. In Hyper-V it’s called Live Migration.
“So, what makes them different, then?”
I’m glad you asked. Just as Microsoft doesn’t make you pay extra for virtualization, we also include the live migration of virtual machines and storage for no additional cost. In the new version of Hyper-V, we no longer limit you in how many simultaneous migrations you can perform at a time. And while clustering is still important for the sake of automating high-availability, we even allow you to perform something called a “Shared Nothing Live Migration”, where, with absolutely zero downtime, you can move a virtual machine between two otherwise unrelated physical hosts, and where the machine is just running on local storage. In my datacenter (aka spare bedroom that is my office) I demonstrate moving a running virtual machine from the C: drive of one old laptop to another’s C: drive, all while remote-desktop connected to the running virtual machine. It’s magical.
Here’s a chart** comparing the free vSphere Hypervisor, vSphere (the purchased product), and Hyper-V in Windows Server 2012.
And yes, the free Microsoft Hyper-V Server can do everything that Hyper-V in Windows Server 2012 can do.
Want more details?
**I realize that things change. VMware will likely soon improve their capabilities to better compete with Microsoft’s Hyper-V. As they should. These numbers come from a good talk given by Matt McSpirit at TechEd North America 2012. I highly recommend viewing the recording of his session HERE.
Have you tried a “shared nothing” migration yet? Let me know if you have any questions on getting it configured. And if you have any opinions at all on the topic, we can discuss it in the comments.