In the last two blogs, I discussed the importance of HA for unplanned host downtime. Today, let’s talk about planned downtime, Quick Migration and Live Migration. Let’s start by understanding the primary usage scenario. Specifically, why do customers require migration capability?
For planned downtime, there are two primary reasons:
1. Hardware servicing. The underlying hardware needs additional storage, memory, or a BIOS update. The server needs to be taken offline and customers want to quickly move virtual workloads off the server for this scheduled maintenance.
2. Patching the Root/Host operating system. If the root partition needs to be patched and that patch requires a reboot, then customers want to quickly move virtual machines off the server for this scheduled maintenance. (This is a good time to point out that the best practice for running Hyper-V will be to do so with a Server Core installation which will reduce the need to patch Windows because it’s running a minimal footprint.)
We’ve drilled into these scenarios further and asked customers, who have currently have Live Migration capabilities, if they have changed their servicing process. In particular, when do they perform their hardware servicing. Is it during business hours 9-5? The overwhelming answer is, “No, we still schedule server downtime and notify folks of the scheduled downtime.”
Even customers with Live Migration still wait until off hours to service the hardware.
What’s my point?
My point is that if you’re scheduling downtime to service the virtualization server and you’re doing it off hours, the difference between sub-second downtime (Live Migration) and even 5, 10, 20 seconds of downtime (Quick Migration) is less of an issue than you might think at a fraction of the cost.
My suggestion: just try it. 🙂
One last benefit with HA/Quick Migration capability is that when you set up this configuration, you’re actually setting up solutions for both planned and unplanned downtime at the same time because they use the same underlying Failover Clustering technology.
BTW: Many of us will be at Microsoft Management Summit (MMS) next week in Las Vegas and hope to see you there.
Q: What are the system requirements for High Availability/Quick Migration?
A: Hyper-V High Availability/Quick Migration requires:
1. Windows Server 2008 Enterprise or Datacenter x64 Editions. High Availability/Quick Migration requires Windows Failover Clustering which is available in Windows Server 2008 Enterprise and Datacenter Editions.
2. Shared Storage. Failover clustering requires shared storage in the form of a SAN (iSCSI, Fiber Channel or SAS).