I’m not going to write about all the vs points against the two products but this one feature which in my opinion is one of the most important (after Live Migration/vMotion). We have come across a few customers who have decided to implement Hyper-V over VMware to save some money. If you compare a feature list of the each product you will see both support HA. But in reality this tick on the list is only part of the story.

I must also point out that in my opinion VMware provides some very attractive essentials bundle which would represent a very small proportion of a new solution. So if it comes down to spending an extra £2k on top of £50K to get it right I know which one I would choose.

Back to HA. Here is my concern, with VMware you tick a box that’s it protected and working. vSphere 5.0 maintains quorum using heartbeats sent over the management network and shares storage devices. Result. Hyper-V you have to delve into the Microsoft clustering wizard. I am not saying this is difficult but it isn’t as easy to get right as ticking a box.

Also and here is my biggest concern. Microsoft clustering relies on Active Directory. This really means keeping a physical domain controller somewhere.  Or a more complex placement of virtual domain controllers. Not getting into the argument of physical DC’s but with VMware for some years now we have rolled our 100% virtual environments without any issue. Just make sure the DC with the PDC emulator role is syncing with an external time source.

Too many times have we had support calls from companies who running Hyper-V clusters who have had issues with HA kicking in the event of a host failure. They either have a physical domain controller and for whatever reason AD isn’t working as expected or they have tied 2 DC’s to separate Hyper-V hosts which happen to be the two hosts in the cluster experiencing some sort of issue.

I’m not saying it is impossible to get this right, but it isn’t the same as ticking a box So how much has that Hyper-V HA feature cost you? You now have a dedicated server running Active directory costing you money in power and maintenance every day.

I should also point out that both VMware and Hyper-V require a solid storage and network infrastructure regardless of the setup requirements of HA.

I will also add that I like the fact Microsoft are pushing at VMware and it is very important that they have competition. Currently though if I am responsible for large IT virtual environment investments it has to be VMware.