# Amazon Elastic Block Store (EBS)

# Overview

It’s a network drive (i.e. not a physical drive)
- It uses the network to communicate the instance, which means there might be a bit of latency
- It can be detached from an EC2 instance and attached to another one quickly
- only be mounted to one instance at a time (at the CCP level)
It's locked to an Availability Zone (AZ)
- An EBS Volume in us-east-1a cannot be attached to us-east-1b
- To move a volume across, you first need to snapshot itme
Have a provisioned capacity (size in GBs, and IOPS)
- You get billed for all the provisioned capacity
- You can increase the capacity of the drive over time.
It allows your instances to persist data, even after their termination (Delete on Termination attribute)

Analogy: Think of them as a “network USB stick”
Free tier: 30 GB of free EBS storage of type General Purpose (SSD) or Magnetic per month

Setup rules to retain deleted snapshots so you can recover them after an accidental deletion
Specify retention (from 1 day to 1 year)

EBS Volumes come in 6 types
- gp2 / gp3 (SSD): General purpose SSD volume that balances price and performance for a wide variety of workloads
- io1 / io2 (SSD): Highest-performance SSD volume for mission-critical low-latency or high-throughput workloads
- st1 (HDD): Low cost HDD volume designed for frequently accessed, throughput intensive workloads
- sc1 (HDD): Lowest cost HDD volume designed for less frequently accessed workloads
EBS Volumes are characterized in Size | Throughput | IOPS (I/O Ops Per Sec)
When in doubt always consult the AWS documentation – it’s good!
Only gp2/gp3 and io1/io2 can be used as boot volumes

Cost effective storage, low-latency
System boot volumes, Virtual desktops, Development and test environments
1 GiB - 16 TiB
gp3:
- Baseline of 3,000 IOPS and throughput of 125 MiB/s
- Can increase IOPS up to 16,000 and throughput up to 1000 MiB/s independently
gp2:
- Small gp2 volumes can burst IOPS to 3,000
- Size of the volume and IOPS are linked, max IOPS is 16,000
- 3 IOPS per GB, means at 5,334 GB we are at the max IOPS

Critical business applications with sustained IOPS performance
Or applications that need more than 16,000 IOPS
Great for databases workloads (sensitive to storage perf and consistency)
io1/io2 (4 GiB - 16 TiB):
- Max PIOPS: 64,000 for Nitro EC2 instances & 32,000 for other
- Can increase PIOPS independently from storage size
- io2 have more durability and more IOPS per GiB (at the same price as io1)
io2 Block Express (4 GiB – 64 TiB):
- Sub-millisecond latency
- Max PIOPS: 256,000 with an IOPS:GiB ratio of 1,000:1
Supports EBS Multi-attach

Cannot be a boot volume
125 GiB to 16 TiB
Throughput Optimized HDD (st1)
- Big Data, Data Warehouses, Log Processing
- Max throughput 500 MiB/s – max IOPS 500
Cold HDD (sc1):
- For data that is infrequently accessed
- Scenarios where lowest cost is important
- Max throughput 250 MiB/s – max IOPS 250

Use case:

Achieve higher application availability in clustered Linux applications (ex: Teradata)
Applications must manage concurrent write operations

When you create an encrypted EBS volume, you get the following:

Data at rest is encrypted inside the volume
All the data in flight moving between the instance and the volume is encrypted
All snapshots are encrypted
All volumes created from the snapshot
Encryption and decryption are handled transparently (you have nothing to do)
Encryption has a minimal impact on latency
EBS Encryption leverages keys from Key Management Service (KMS) (AES-256)
Copying an unencrypted snapshot allows encryption
Snapshots of encrypted volumes are encrypted