The Amazon instance store provides ephemeral block-level storage for EC2 instances. The storage is consumed from physical disks attached to the hypervisor and is ideal for the temporary storage of information that changes frequently, such as the operating system paging, buffers, caches, scratch, and other temporary data. It can also be used for data that is securely replicated across a cluster of instances, such as a distributed NoSQL database or Hadoop cluster.

The data written to the instance store volumes exist only while your instance is powered on. That means the data in the instance store will not survive in any of the following cases:

• The underlying disk subsystem fails
• The instance is stopped or the operating system is shut down
• The instance is terminated

The allotted storage from the instance store depends on the instance type and will be represented as one or more volumes (up to 24) that range in size from 4 GB on the smallest to 2 TB on the largest instance types. The instance store volumes are included in the price of the instance type, so we should make use of them whenever we are choosing an instance type that comes with an instance store volume.