-: In this section, we're going to discuss
the importance of planning for the worst.
We're going to do this by conducting redundancy
and disaster recovery planning.
But what exactly is redundancy?
Well, redundancy is a term that usually refers
to something that's extra or unnecessary.
For example, if I'm sitting at a restaurant
and my waitress brings me over two glasses of water
instead of one, well, one of those glasses is redundant
because I can only drink from one glass at a time.
Now, in the IT world though, we love redundancy.
Redundancy is a great thing.
Let's say I have one server
that I need to run a domain controller.
Well, it's probably a better idea for me to have
two servers to run that domain controller.
One is a primary and one is a backup,
in case that primary fails.
Also if I have a connection to the Internet,
wouldn't it be better if I had
two connections to the Internet?
Your cell phone knows this is true
and that's why you have two different ways to connect.
You have a cellular modem in there
that connects to the cellular network,
and you have wireless access,
where you can connect to your Wi-Fi.
That's the same idea, you have two different methods,
which give you the same features and they are redundant.
So I think you understand the concept of redundancy
and why it may be a good thing inside of IT.
So, when we do redundancy planning,
we're looking at our networks, our servers,
and our systems to make sure that they're fault-tolerant,
and we want to make sure that they can
continue to provide us services 24 hours a day,
seven days a week, 365 days a year.
To do this, we have to identify any single points of failure
inside of our networks and our systems,
and those single points of failure
are those individual elements, objects, or parts
that could cause a system to fail
and if one of those components fails,
it'll take down the entire system with it.
Now, if we can identify those single points of failure,
then we can design backup and redundant systems
around them to eliminate them or mitigate them.
And this way, we're going to be able
to increase our availability and increase our uptime.
The reality is, though, that when we plan
for everything to go right, sometimes things still go wrong,
and this is where disaster recovery comes into play.
We're going to do disaster recovery to figure out
how we're going to do our backup systems
and how they're designed, and how we're going
to conduct disaster recovery planning
in case our building catches on fire,
or we have floods, or earthquakes,
or any of a myriad of other things that can happen
and how we're going to overcome them and get back to business.