What is the process of Hyper‑V Replica failover and failback?
Well, it's a lot easier than ASR for sure,
because here we're talking about not an orchestration
among multiple related machines, but basically single virtual machines.
And because AZ‑801 is an exam that deals with administration and implementation,
you can expect to see questions that require you to know where user
interface elements are. Now before you think,
well, wait a minute, Tim,
isn't that trivia, not so fast. Remember that Microsoft is looking to
validate that you not only understand the theory of,
say, Hyper‑V Replica,
but you know how to use it. And if you've gotten enough time or
spent enough time using the technology in a practice test lab
or even a production environment,
then it's probably not that big a deal for you to answer these questions.
So here I want to show you the user interface options that you see on
both your primary and secondary Hyper‑V hosts. Here I want to draw your
attention. What I've got in Hyper‑V Manager,
I've got mem1, which is my primary host selected, and I
furthermore right‑clicked on win1, which is a virtual
machine running in that primary host.
And notice the options you get. Right‑click Replication. You get
Planned Failover, but you don't get the Failover option.
Why do you think that's the case? Well,
how could you do a failover from the primary if the primary site is
unavailable or if the primary host is gone? The whole idea with replication
is that we're providing that high availability. So notice that you can
remove and pause and view replication health,
but you can initiate only planned failover,
which, again, is a great practice for you and your team to adopt so you can
build up that muscle memory and see what happens when a failover actually
occurs, all right? And planned also makes it a lot easier for you to undo the
change. It'll actually, a planned failover will create a separate VM that you
can just delete on the secondary server.
So let's now look over to the partner, or the secondary Hyper‑V host, mem2,
and notice that the replicated VM, win1, is in an off state. It is being
actively replicated, and you can verify that by right‑clicking the virtual
machine and going to Replication,
View Replication Health. But notice that there is some additional options. Yes,
there's Test Failover,
but I want you to see that the actual failover control is on the
secondary, and that should make all the sense in the world from a
logic standpoint when you think of the disaster recovery
underpinnings of this technology. Now,
what is Extend? Pause Replication, that's pretty easy to
understand, but what about Extend Replication?
Well,
Extend is where you can create a standby of a standby. If you
want more than one level of disaster recovery,
you can take this secondary and then extend it to yet a third
Hyper‑V host. It kind of gets, in my opinion,
a little bit abstract and reminds me of the old movie Inception,
if you remember that.
But that just is a feature that's baked in here that gives some
businesses that extra level of redundancy that they might need to protect a virtual machine workload in Hyper‑V.