A block device mapping defines the block devices (instance store volumes and EBS volumes) to attach to an instance. You can specify a block device mapping as part of creating an AMI so that the mapping is used by all instances launched from the AMI.

What is a block device mapping?

A block device mapping defines the block devices (instance store volumes and EBS volumes) to attach to an instance. You can specify a block device mapping as part of creating an AMI so that the mapping is used by all instances launched from the AMI.

When you view the block device mapping for your instance you can see only the EBS volumes not the instance store volumes?

View the block device mapping for an instance, only the EBS volumes can be seen, not the instance store volumes. Instance metadata can be used to query the complete block device mapping.

How do I know if my disk is ephemeral?

There are three ways to know if EC2 Storage is ephemeral.

  1. According to Understand the Instance Store and EBS article which discuss why there are instance that lost its data if stopped/terminated. You have to run the lsblk linux command.
  2. You can check your instance type.
  3. Query the metadata server using:

What is ephemeral in AWS?

Ephemeral: Instance store volumes also known as virtual devices have underlying hardware physically attached to the host computer for the instance. Instance store volumes support ephemeral [0-23]. Whenever you launch an EC2 instance, the instance store volume type is ephemeral by default.

What is a root block device?

The Root device is the EBS volume for the AMI in which your instance is based on. This will contain the operating system. If not configured then, AWS will use the default values of the AMI. You can configure additional Block device entries optionally to mount additional volumes on the instance, besides the root volume.

Is AWS EBS ephemeral?

AWS currently offers the following storage services: Instance/Ephemeral Storage. Elastic Block Storage (EBS) Elastic File System (EFS)

Is EBS ephemeral?

EC2 Instances primarily utilize storage known as EBS Volumes. But this isn’t the only type of storage that is available. There’s another type, known as Instance Store, or Ephemeral Storage.

What is ephemeral drive?

Ephemeral disks are virtual disks that are created for the sole purpose of booting a virtual machine and should be thought of as temporary. Ephemeral disks are useful if you aren’t worried about needing to duplicate an instance or destroy an instance and save the data.

What is ephemeral OS disk Azure?

Ephemeral OS disks are created on the local virtual machine (VM) storage and not saved to the remote Azure Storage. Ephemeral OS disks work well for stateless workloads, where applications are tolerant of individual VM failures but are more affected by VM deployment time or reimaging of individual VM instances.

Which type of AWS storage is ephemeral?

The virtual devices for instance store volumes are ephemeral[0-23] . Instance types that support one instance store volume have ephemeral0 . Instance types that support two instance store volumes have ephemeral0 and ephemeral1 , and so on.

Which storage type is ephemeral?

Ephemeral storage is storage that is associated only to a specific Compute instance. Once that instance is terminated, so is its ephemeral storage. This type of storage is useful for basic runtime requirements, such as storing the instance’s operating system.

How to automate the check for ephemeral devices attached to instance?

Or, you can automate the check to display the ephemeral devices attached to your instance by using the following set of commands. Identify the OS block devices. Set the block device mapping URL. Loop through OS devices and find the mapping in the block device mapping.

What is block device mapping?

The block device mapping is used by Amazon EC2 to specify the block devices to attach to an EC2 instance. After a block device is attached to an instance, it must be mounted by the operating system before you can access the storage device.

How to query the NVMe instance in Block Device Mapping?

You can use the NVMe command line package, nvme-cli, to query the NVMe instance store volumes in the block device mapping. Download and install the package on your instance, and then run the following command.

Should I include M3 volumes in my Block Device Mapping?

Including them in your block device mapping has no effect. Constraints: For M3 instances, you must specify instance store volumes in the block device mapping for the instance.