Elastic Block Storage

Elastic Block Storage

-       https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AmazonEBS.html

-       Amazon Elastic Block Store (Amazon EBS) provides block level storage volumes for use with EC2 instances. EBS volumes behave like raw, unformatted block devices. You can mount these volumes as devices on your instances. EBS volumes that are attached to an instance are exposed as storage volumes that persist independently from the life of the instance. You can create a file system on top of these volumes, or use them in any way you would use a block device (such as a hard drive). You can dynamically change the configuration of a volume attached to an instance.

Elastic Block Store vs. Instance store

-       Elastic Block Store volume is network attached drive which results in slow performance, but data is persistent meaning even if you reboot the instance data will be there. 

-       Instance store is physically attached device which gives better performance, but data will be lost once instance is rebooted

-       Instant store – ephemeral – CAN NOT be added once an instance is launched. Needs to be specified at launch time.

-       On the console – only EBS volumes are shown. Need to run curl to see Instance Store and EBS together

-       EBS provides 99.999% availability

-       Can create point-in-time snapshots of EBS instances

Storage Types:
-       https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-volume-types.html

Provisioned IOPS (SSD)
- SSD backed
- Use case: critical apps – I/O intensive, SQL/NoSQL db
- Max IOPs – 64,000
- The maximum ratio of provisioned IOPS to requested volume size (in GiB) is 50:1. For example, a 100 GiB volume can be provisioned with up to 5,000 IOPS. On a supported instance type, any volume 1,280 GiB in size or greater allows provisioning up to the 64,000 IOPS maximum (50 × 1,280 GiB = 64,000)

- 4-16 TiB (Tibibyte = TiB = 2^40 bytes)

General purpose (SSD)
- SSD-Backed – solid state drives
- Use case: Transactional w/loads: small db & boot volumes, Dev/Test env, Low latency interactive apps (IOPS dependent)
- 1-16 TiB (Tibibyte = TiB = 2^40 bytes)
- Max IOPS – 16,000

Throughput Optimized HDD (not SDD)
- Use case: steaming, big data log processing data warehouse
- Can NOT be used as boot volume
- Use for frequently accesses throughput intensive workloads
- Size 500 GiB - 16 TiB

Cold HDD
- Use case: not frequently accessed workloads
- CAN NOT be the root volume
- Size 500 GiB - 16 TiB

Magnetic EBS
- For txn workloads where performance is not dependent on IOPS but on MB/Sec transfer rate
- HDD backed
- Used for infrequently accessed data

- Size 1GiB - 1 TiB