‫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.