This decoupling allows you to attach the same volume to different EC2 instances (one at time). One of the core principles of designing robust, highly available applications is to decouple compute from storage. Data stored in an EBS volume is retained even when the EC2 instance as well as the underlying physical host is restarted (stop and start), rebooted or terminated. EBS: What is Elastic Block Storage (EBS Storage)?Įlastic Block Storage provides another type of storage abstraction and is one of the most popular storage services providing persistent data storage. However, the applications created using ephemeral disk must be resilient in order to recover from failures when there is a change in the underlying host. Instance disk storage can be used as a scratch pad for storing temporary objects, for example, while transforming original objects to a new format (to be stored in an EBS volume and/or S3). One of the characteristics of the AWS infrastructure is that when an EC2 instance is stopped and restarted, the underlying host will always change.Īs a result, the original mount point of the ephemeral disk would not be available in the new host. Furthermore, there is no charge associated with the ephemeral storage.Ĭontent stored in ephemeral storage survives reboots, however, when an EC2 instance is stopped, terminated or restarted, all the content stored in the instance storage is lost. As a result, the disk access is extremely fast, setting aside the constraints of the physical media. Since the storage is local to the host, there is no network I/O overhead for reading or updating the content. When an EC2 instance/container is launched, a mount point can be created in the Guest VM and mounted to a portion of the disk from the underlying host. What is Ephemeral Storage (Instance Storage)?Įach EC2 guest instance (or container) can use the disk storage attached to the physical host. The end use cases dictate the optimal storage service to be used in different scenarios. The last item in the list, S3 ecosystem, is centered around the object storage.
Aws ephemeral storage portable#
These three offer Portable Operating System Interface (POSIX) compliances. The first three items in the list above - ephemeral storage, elastic block storage and elastic file system - are different abstractions around block storage.
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