Amazon Elastic Block Store (Amazon EBS)
Amazon provides block level storage via EBS for Elastic EC2 instances. Multiple EBS volumes can be attached to single Amazon EC2 instance although a volume can only be attached to a single instance at a time.
Types of Amazon EBS Volumes
There are various types of EBS volumes available or provided by AWS. Some of them are discussed below.
Magnetic Volumes: Magnetic volumes are the lowest performance volume range in size from 1 GB to 1 TB and will average 100 IOPS, but has the ability to burst to hundreds of IOPS. They are best suited for:
- Workloads where data is accessed infrequently
- Sequential reads
- Situations where low-cost storage is a requirement
General-Purpose SSD: General-purpose SSD volumes are cost-effective storage and deliver strong performance. SSD volume can range in size from 1 GB to 16 TB and provides a baseline performance of three IOPS per gigabyte provisioned, capping at 10,000 IOPS. General-purpose SSD volumes are billed based on the amount of data space provisioned, regardless of how much data you actually store on the volume. They are suited for:
- System boot volumes
- Small- to medium-sized databases
- Development and test environments
Provisioned IOPS SSD: Provisioned IOPS SSD volume are mainly used for I/O-intensive workloads and database workloads that are sensitive to storage performance. A Provisioned IOPS SSD volume can range in size from 4 GB to 16 TB. While provisioning an IOPS SSD volume, you specify not just the size, but also the desired number of IOPS, up to the lower of the maximum of 30 times the number of GB of the volume, or 20,000 IOPS.
Provisioned IOPS SSD volumes provide predictable, high performance and are well suited for:
- Critical business applications that require sustained IOPS performance
- Large database workloads
There are need to protect data on AWS EBS volume, there are following ways that is required to protect data.
Taking Snapshots: Snapshots can be taken in many ways:
- Through the AWS Management Console
- Through the CLI
- Through the API
- By setting up a schedule of regular snapshots
Data for the snapshot is stored using Amazon S3 technology. The action of taking a snapshot is free. You pay only the storage costs for the snapshot data.
Creating a Volume from a Snapshot: A new Amazon EBS volume can be created from snapshot. The volume is created immediately but the data is loaded lazily. This means that the volume can be accessed upon creation, and if the data being requested has not yet been restored, it will be restored upon first request.
Recovering Volumes: When an instance fails, its associated volume can be recovered. In this the DeleteOnTermination flag for the volume is set to false, the volume is than detached before the instance is terminated. The volume is than attached as a data volume to another instance and the data read and recovered.