Again, instance store volumes have the designation "ephemeral#" where # is some integer from 0 to 23.

Block Device Mapping of instance store volumes can occur on either Linux or Windows, even if the instance type does not officially support the use of instance store volumes.

This can occur when using the

AWS CLI, an SDK, or a service such as CloudFormation to launch an EC2 instance based upon an AMI with a block device mapping that includes instance store volumes. If the EC2 console is used to launch an EC2 instance type that does not support instance store volumes (such as T2, M4, or C4), modified block device mappings are simply ignored.

Remove or override any references to instance store volumes in the AMI, and relaunch the EC2 instance

If you verify that your EC2 instance is using an instance store volume, you must relaunch the instance because instance store volumes cannot be added or removed from an existing EC2 instance. You can remove references to instance store volumes from the AMI and relaunch the instance, or use one of the following methods to override references to instance store volumes in the AMI when you relaunch the EC2 instance:

• Launch the EC2 instance from the EC2 console to override the AMI for those EC2 instance types that do not support instance store volumes.
• Launch the EC2 instance from the AWS CLI and manually override each device in the AMI that references an instance store volume. In the example AWS CLI output shown earlier, the devices mapped to instance store volumes are '/dev/sdb' and '/dev/sdc'. To override mapping of these devices to instance store volumes, you can launch the EC2 instance from the CLI using the following syntax: