Narrator: So we've seen a way to attach a network drive
onto our EC2 Instances
but they have limited performance
and I said with cause because it's a really good performance
but sometimes you want something even higher performance
and that is going to be a hardware disk
attached onto you EC2 Instance.
So the EC2 Instance is a virtual machine
but it is obviously attached to a real hardware server.
And some of these servers do have disk space
that is attached directly you know,
with a physical connection onto the server.
And so a special type of EC2 Instance can leverage
something called an EC2 Instance Store,
which is the name of the hardware,
the hard drive attached to the physical server.
So what we do with EC2 Instance Store,
we use them for better I/O performance.
We also make sure that they have good through put
and so on, so they're a great choice
when you want to have extremely high disk performance.
But the caveat is that if you stop
or you terminate your EC2 Instance,
that has an Instance Store,
then the storage will be lost.
And therefore it's called an ephemeral storage
so that means that the EC2 Instance Store
can now be used as a durable long term place
to store your data.
So what is a good use case for it then?
Well if you have a buffer, a cache,
you want to have scratch data or temporary content,
this would be a great place to do these things
but not for long term storage.
For long term storage, EBS for example
is a great use case.
Finally, in case the on the line server
of the EC2 Instance does fail,
then you'll risk to have a dear loss
because the hardware attached to the EC2 Instance
will fail as well.
So if you do decide to use an EC2 Instance Store,
then it is your entire responsibility
to make sure that you back it up
and that you replicate it correctly based on your needs.
So what I mean by better performance,
this is just an example to illustrate it,
don't need to know it.
But if you look at for example,
the Instance size of I3 dot something,
there is an Instance Store attached
to these kinds of instances
and if you look at the Read IOPS
and the Write IOPS
which correspond to how many I/O operations
we can do per second.
Then you can see at some of these random Read IOPS
and Write IOPS can reach 3.3 million or 1.4 million,
for the most performant one.
And to put this in comparison
with an EBS volume of type BP2 for example,
you can reach thirty two thousand IOPS.
So this is a lot more.
But again, it's just to illustrate my point
from an exam perspective anytime you see very
high performance hardware attached volume
for your EC2 Instances, think local EC2 Instance Store.
That's it.
I will see you in the next lecture.