3.4 AWS Instance Store vs Elastic Block Store Volume

AWS EC2 Instance Store
An instance store provides temporary block-level storage for your instance.
This storage is located on disks that are physically attached to the host computer.
Instance store is ideal for temporary storage of information that changes frequently, such as buffers, caches, scratch data, and other temporary content.
You can't detach an instance store volume from one instance and attach it to a different instance.
The data in an instance store persists only during the lifetime of its associated instance.
If an instance reboots (intentionally or unintentionally), data in the instance store persists.
However, data in the instance store is lost under any of the following circumstances:
The underlying disk drive fails
The instance stops
The instance terminates.
Amazon Elastic Block Store (Amazon EBS)
Amazon Elastic Block Store (Amazon EBS) provides block level storage volumes for use with EC2 instances.
Amazon Elastic Block Store (Amazon EBS) provides block level storage volumes for use with EC2 instances. EBS volumes behave like raw, unformatted block devices.
You can mount these volumes as devices on your instances. 
One EBS volume can only be attached to a single instance at a time.
Amazon EBS provides the following volume types:
General Purpose SSD (gp2).
Provisioned IOPS SSD (io1).
Magnetic Volumes
Throughput Optimized HDD (st1).
Cold HDD (sc1).