In the last two posts [Part-1, Part-2] of this series, we 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?