amazon ebs

Elastic Block Storage (EBS):

Elastic block volume storage is like a volume storage (hard disk). This ebs is attached to the running amazon ec2 as we seen early post about amazon ec2.

Amazon Elastic Block Store provides highly available, highly reliable storage volume

Features of Amazon EBS volumes:

• Amazon EBS allows you to create storage volumes from 1 GB to 1 TB that can be mounted as devices by Amazon EC2 instances. Multiple volumes can be mounted to the same instance.
• Storage volumes behave like raw, unformatted block devices, with user supplied device names and a block device interface. You can create a file system on top of Amazon EBS volumes, or use them in any other way you would use a block device (like a hard drive).
• Amazon EBS volumes are placed in a specific Availability Zone, and can then be attached to instances also in that same Availability Zone.
• Each storage volume is automatically replicated within the same Availability Zone. This prevents data loss due to failure of any single hardware component.
• Amazon EBS also provides the ability to create point-in-time snapshots of volumes, which are persisted to Amazon S3. These snapshots can be used as the starting point for new Amazon EBS volumes, and protect data for long-term durability. The same snapshot can be used to instantiate as many volumes as you wish.

Amazon EBS snapshot :

Amazon EBS provides the ability to back up point-in-time snapshots of your data to Amazon S3 for durable recovery. Amazon EBS snapshots are incremental backups, meaning that only the blocks on the device that have changed since your last snapshot will be saved. If you have a device with 100 GBs of data, but only 5 GBs of data has changed since your last snapshot, only the 5 additional GBs of snapshot data will be stored back to Amazon S3. Even though the snapshots are saved incrementally, when you delete a snapshot, only the data not needed for any other snapshot is removed. So regardless of which prior snapshots have been deleted, all active snapshots will contain all the information needed to restore the volume. In addition, the time to restore the volume is the same for all snapshots, offering the restore time of full backups with the space savings of incremental.

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