You work for a company that has a set of EC2 Instances. There is an internal requirement to create another instance in another availability zone. One of the EBS volumes from the current instance needs to be moved from one of the older instances to the new instance. How can you achieve this?

Answer options:

A.Detach the volume and attach to an EC2 instance in another AZ.
B.Create a new volume in the other AZ and specify the current volume as the source.
C.Create a snapshot of the volume and then create a volume from the snapshot in the other AZ
D.Create a new volume in the AZ and do a disk copy of contents from one volume to another.

Answer – C
For a volume to be available in another availability zone, you need to create a snapshot from the volume. Then in the snapshot from creating a volume, you can then specify the new availability zone accordingly.
The EBS Volumes attached to the EC2 Instance will always have to remain in the same availability zone as the EC2 Instance. A possible reason for this could be because EBS Volumes are present outside of the host machine, and instances have to be connected over the network. If the EBS Volumes are present outside the Availability Zone, there can be potential latency issues and subsequent performance degradation.
What one can do in such a scenario is to get the Snapshot of the EBS Volume. Snapshot sequentially captures the state of your EBS Volume. You can create an EBS Volume from this snapshot in your desired Availability Zone and attach it to your new Instance.
Later you can detach the volume from the older instance and delete then.
Option A is invalid because the Instance and Volume have to be in the same AZ to be attached to the instance. After all, we have to specify AZ while creating Volume.
Option B is invalid because there is no way to specify a volume as a source.
Option D is invalid because the Diskcopy would be a tedious process.
For more information on snapshots, please visit the below URLs-
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSSnapshots.html
https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/ebs-detaching-volume.html