AWS Storage Services : Amazon EBS — AWS Solutions Architect

Amazon EBS

Overview

Amazon Elastic Block Store volumes provide durable block-level storage for use with EC2 instances. The volumes are network-attached storage that persists independently from the running life of a single EC2 instance. Most AMIs are backed by Amazon EBS and use an EBS volume to boot EC2 instances. Also multiple EBS volumes can be attached to a single EC2 instance. However, any single EBS can be attached to only one EC2 instance.

EBS snapshots can be created at any time and stored in Amazon S3. The snapshots are used to create new EBS volumes. The same snapshot can be used to instantiate as many volumes as required. These snapshots can be copied across AWS Region.

Sizes for EBS volumes range from 1GiB to 16 TiB, depending on the volume type, and are allocated in 1 GiB increments.

Usage Patterns

• well-suited for use as the primary storage for a database or file system
• a rage of options to optimize storage performance and cost for your workload
• SSD-backed storage for transactional workloads such as databases and boot volumes(performance primarily depends on IOPS)
• HDD-backed storage for throughput-intensive workloads such as big data, data warehouse, and log processing(performance depends primarily on MB/s)

Storage Needs for which you should consider other AWS storage options

Performance

• SSD-backed storage volumes offer great price/performance characteristics for small block workloads
• HDD-backed storage volumes offer the best price/performance characteristics for large block sequential workloads
• can attach and stripe data across multiple volumes of any type to increase I/O performance
• Storage Characteristics of the current generation volume types

General Purpose SDD(gps)

• ideal for a broad range of workloads
• single digit millisecond latencies
• burst to 3,000 IOPS for extended periods of time
• baseline performance of 3 IOPS/GiB up to a max of 10,000 IOPS
• range in size from 1GiB to 16 TiB
• Throughput limit range of 128 MiB/second for volumes less than equal to 170 GiB
• For volumes over 170 GiB, the limit increases at the rate of 768 KiB/second per GiB to a max of 160 MiB/second(at 214 GiB and larger)
• can check the percentage of I/O credits remaining in the burst buckets for gp2 volumes by viewing the BurstBalance metric in Amazon CloudWatch

Provisioned IOPS SSD(io1)

• designed for high performance I/O intensive workloads with small I/O size
• Size ranges from 4GiB to 16TiB
• provision up to 20,000 IOPS per volume
• The ratio of IOPS provisioned to the volume size requested can be a maximum of 50

Throughput Optimized HDD(st1)

• ideal for frequently accessed workloads
• large datasets and large I/O sizes such as big data, data warehouse, log processing, and ETL workloads
• burst up to 250 MiB/s per TiB
• Maximum throughput of 500 MiB/s per volume
• can’t be used as boot volumes

Cold HDD(sc1)

• the lowest cost per GiB of all EBS volume types
• infrequently accessed workloads with large, cold, datasets with large I/O sizes
• a burst model can burst up to 80 MiB/s per TiB with a baseline throughput of 12 MiB/s per TiB and a maximum throughput of 250 MB/s per volume.
• 99 percent of the time, enough I/O credits to support a full-volume scan at the burst rate

EBS-optimized EC2 instances ( m4, c4, x1, and p2) deliver dedicated throughput between Amazon EC2 and Amazon EBS with speeds between 500 Mbps and 10,000 Mbps depending on the instance type.

Durability and Availability

• Volume data replicated across multiple servers in a single Availability Zone to prevent the loss of data from the failure of any single component
• taking snapshots increases the durability of data stored on your EBS volumes
• EBS snapshots are incremental, point-in-time backups
• Annual failure between 0.1 and 0.2 percent
• For application-consistent backups, brief pausing any write operations or unmounting the volume is recommended while snapshotting.

Scalability and Elasticity

• rapid provisioning and releasing EBS volumes to scale in and out are possible using AWS management console and EBS API.
• Volume resize : 1) detach the original EBS volume, 2) Create a snapshot of the original EBS volume’s data in Amazon S3, 3) Create a new EBS volume from the snapshot but specify a larger size than the original one, 4) Attache the new one to your EC2 instance, 5) Delete the original EBS volume

Security

• IAM access control for EBS volumes
• Encryption for data-at-rest and data-in-motion
• Encryption keys are Amazon-managed or keys that you create and manage using AWS Key Management Service

Interfaces

• REST API, AWS SDKS, AWS CLI: create, delete, describe, attach, and detach EBS; create, delete, describe snapshots
• No data API

Cost Model

• Pay only for what you provision
• For hard disks, pay for the entire size of the disk
• Pricing has 3 components: provisioned storage, I/O requests, and snapshot storage
• gps, st1, sc1 volumes are charged per GB-month of provisioned storage
• io1 volumes are charged per GB-month of provisioned storage and per provisioned IOPS-month.
• snapshots are charged per GB-month of data stored
• snapshot copy is charged per the data transferred between Regions
• for the standard Amazon EBS snapshot charges in the destination Region
• No charge for transferring information among the various AWS storages as long as they are in the same AWS Region