‫Welcome to this section
‫where we will at look the different storage options
‫for EC2 instances.
‫So first, the most important ones
‫are going to be EBS Volumes, so let's define what they are.
‫An EBS Volume stands for Elastic Block Store.
‫It's a network drive that you can attach to your instances
‫while they run,
‫and we've been using them without even knowing.
‫So this EBS Volumes allow us to persist data,
‫even after the instance is terminated.
‫And so that's the whole purpose,
‫we can recreate an instance
‫and mount to the same EBS Volume from before
‫and we'll get back our data.
‫That is very helpful.
‫So these EBS Volumes, at the CCP level,
‫can only be mounted to one instance at a time, okay?
‫And when you create an EBS Volume,
‫it is bound to a specific availability zone.
‫That means that you cannot have an EBS Volume
‫in created, for example, us-east-1a
‫we'll see this in the diagram in a second.
‫So how do you think of EBS Volumes?
‫Well, you can think of them as network USB sticks.
‫So, it's a USB stick that you can take from a computer
‫and put it in another computer
‫but you actually don't physically put it in a computer.
‫It's attached through the network.
‫The feature gives us 30 GBs of free EBS storage
‫of type General Purpose or SSD or Magnetic per month.
‫And in this course, we'll be using this
‫with the GP2 to GP3 Volumes.
‫Now let's look at it.
‫So EBS Volumes are network drivers
‫that is not a physical drive, okay?
‫So to communicate between the instance and the EBS Volume,
‫it will be using the network.
‫And because the network is used,
‫there may be a bit of latency from one computer
‫to reach to another server.
‫Now, EBS Volumes, because they are a network drive
‫they can be detached from an EC2 instance
‫and attached to another one very quickly.
‫And that's makes it super handy
‫when you want to do failovers for example.
‫EBS Volumes are locked to a specific availability zones,
‫that means that, as I said, if it's created in us-east-1a
‫it cannot be attached to us-east-1b
‫but, we will see in this section that if we do a snapshot,
‫then we are able to move a volume across
‫from different availability zones.
‫And finally, it's a volume,
‫so you have to provision capacity in advance.
‫So you need to say how many GBs you want in advance
‫and the IOPS, which is I/O operations per seconds,
‫and you're basically defining how you want
‫your EBS Volume to perform.
‫You're going to get billed for that provision capacity
‫and you can increase the capacity over time
‫if you want you to have better performance or more size.
‫So, as a diagram, how does it look like?
‫Well, we have us-east-1a with one EC2 instance
‫and we can attach, for example
‫one EBS Volume to the EC2 instance.
‫If we create another EC2 instance,
‫as I said an EBS Volume can not be attached to two instances
‫at a time at the Certified Cloud Practitioner level.
‫And therefore, what I wanna say is that
‫this other EC2 instance needs to have
‫its own EBS Volume attached to it,
‫but it is a very possible for us to have two EBS Volumes
‫attached to one instance
‫think of it as two network USB sticks into one machine
‫that makes a lot of sense.
‫Now EBS Volumes are linked to an availability zone.
‫So as we can see, all this diagram has been so far using
‫us-east-1a.
‫So if you want it to have other EBS Volumes in an other AZ
‫then you would need to create this separately
‫in the other availability zone.
‫So just same way that's your EC2 instances
‫are bound to an AZ, so are the EBS Volumes.
‫Finally, it is possible for us to create EBS Volumes
‫and leave them unattached
‫they don't need to be necessarily attached
‫to an ECG instance, they can be attached on demand
‫and that makes it very, very powerful.
‫Finally, when we go ahead and create EBS Volumes
‫through EC2 instances, there is this thing
‫called a Deletes on Termination attribute
‫and this can come up in the exam so,
‫if you look at this when we create
‫an EBS Volume in the console, when we create an EC2 instance
‫there is the second to last column
‫called Delete on Termination.
‫And by default, it is ticked for the Root Volume
‫and not ticked for a new EBS Volume.
‫So this controls the EBS behavior
‫when an EC2 instance is being terminated.
‫So by default, as we can see, the root EBS Volume
‫is deleted alongside the instance being terminated.
‫So it's enabled
‫and the default any other attached EBS Volume is not deleted
‫because it's disabled by default.
‫But obviously as we can see in this UI, we can control
‫if you want to enable or disable delete on termination.
‫And so use case right, would be for example,
‫if you want to preserve the root volume,
‫when an instance is terminated,
‫for example, to save some data
‫then you can disable delete on termination
‫for the root volume, and you'll be good to go
‫and it could be an exam scenario at the exam.
‫So I hope you liked it.
‫And I will see you in the next lecture.