# EBS Snapshots

* You can **back up the data on your EBS volumes to Amazon S3** by taking point-in-time snapshots.\

* Snapshots are **incremental backups** - this means that **only the blocks on the device that have changed after your most recent snapshot are saved**.
  * This **minimizes the time required to create the snapshot** and saves on storage costs by not duplicating data.\

  *   **Each snapshot contains all of the information that is needed to restore your data** (from the moment when the snapshot was taken) to a new EBS volume.


* **When you create an EBS volume based on a snapshot, the new volume begins as an exact replica of the original volume** that was used to create the snapshot.
  * The **replicated volume loads data in the background** so that you can begin using it immediately.\

  * **If you access data that hasn't been loaded yet, the volume immediately downloads the requested data from Amazon S3**, and then continues loading the rest of the volume's data in the background.

## Copying and sharing snapshots

* A **snapshot is constrained to the AWS Region** where it was created.
  * After you create a snapshot of an EBS volume, you can use it to create **new volumes in the same Region**.\

* You can **copy snapshots across Regions, making it possible to use multiple Regions** for geographical expansion, data centre migration, and disaster recovery.

## Restoring an EBS volume

*   Try to **automate and test the restore process** as much as possible to **reduce the risk of your restore process failing** or being implemented inconsistently.


* Data from an Amazon **EBS snapshot is asynchronously loaded into an EBS volume**.\

* If an application accesses the volume where the data is not loaded, there is **higher latency than normal while the data is loaded from Amazon S3**.
  * **To avoid this impact for latency-sensitive applications, you can pre-warm your data from a snapshot into an EBS volume**.\

* You **can restore a non-root volume attached to an existing EC2 instance by creating a volume from a snapshot and attaching it to your instance**.
  * You can then **mount the volume to the instance by using the operating system**.

## Amazon Data Lifecycle Manager (DLM)

* Amazon DLM for EBS Snapshots **provides a simple, automated way to back up data** stored on Amazon EBS volumes.\

* You can **define backup and retention schedules for EBS snapshots by creating lifecycle policies based on tags**.
  * You **no longer have to rely on custom scripts to create and manage your backups**.
