Section 3 - EC2 Instance Storage

Same content! Refer to Section 04 - EC2 Instance Storage

Characterised in size, throughput, IOPS (I/O operations per second)
There are 6 types:
- gp2 / gp3 (SSD): General purpose SSD volume balancing price and performance for a variety of tasks (can be used as boot volume)
- io1 / io2 Block Express (SSD): Best performing SSD volume for mission-critical, low-latency or high-throughput workloads (Can be used as boot volume)
- st1 (HDD): Cheap HDD volume for frequently accessed, throughput-intensive workloads
- sc1 (HDD): Lowest cost HDD volume for less frequently accessed workloads
Use cases:
- General purpose SSD
  - Cost effective storage and low-latency
  - System boot volumes, virtual desktops, development and test environments
- Provisioned IOPS (PIOPS) SSD
  - Critical business applications with sustained IOPS performance
  - Applications that need more than 16,000 IOPS
  - Database workloads (require storage performance and consistency)
  - Supports EBS multi-attach
- HDD
  - Can't be a boot volume

Attach the same EBS volume to multiple EC2 instances in the same AZ
Each instance has full read / write permissions to the volume
Use case:
- Achieve higher application availability in clustered Linux applications
- Applications msut manage concurrent write operations
Can attach up to 16 instances at a time
Need to use a file system that's cluster-aware (not XFS, EXT4, etc...)

Upon creation of an encrypted EBS volume
- Data at rest is encrypted inside the volume
- All data in flight moving between the instance and volume is encrypted
- All snapshots are encrypted
- All volumes created from the snapshot
Encryption and decryption are handled by AWS
Encryption has minimal impact on latency
Leverages keys from KMS (AES-256)
Copying an unencrypted snapshot allows encryption
Snapshots of encrypted volumes are encrypted
To encrypt an unencrypted EBS volume:
- Create an EBS snapshot of the volume
- Encrypt the EBS snapshot using the copy
- Create a new EBS volume from the snapshot (the volume will also be encrypted)
- Can attach the encrypted volume to the original instance now

EFS Scale
- Thousands of concurrent NFS clients, 10 GB+ /s throughput
- Can grow to a Petabyte-scale NFS automatically
Performance Mode
- Set at EFS creation time
- General purpose (default): Latency-sensitive use cases (web server, CMS)
- Max I/O: Higher latency, throughput, parallel (big data, media processing)
Throughput Mode
- Bursting: Can suddenly burst up to 100 MiB/s from 50 MiB/s
- Provisioned: Set a fixed throughput regardless of storage size
- Elastic: Automatically scales throughput up or down, great for unpredictible workloads
Storage Tiers (lifecycle management)
- Standard: Frequently accessed files
- Infrequent access (EFS-IA): Cost to retrieve files, lower price to store
- Archive: Rarely accessed data (few times per year), 50% cheaper
- Leverage lifecycle policies to move files between tiers
Availability and durability
- Standard: Multi-AZ, great for production
- One Zone: Single AZ, great for development, backup enabled by default and compatible with IA (EFS One Zone-IA)
Over 90% in cost savings

EBS
- Used on one instance (except multi-attach io1 / io2)
- Locked at the AZ level
- Migrating an EBS volume across an AZ requires a snapshot and restoring the snapshot in another AZ
- Root EBS volumes of instances get terminated by default if the instance gets terminated (can be disabled)
EFS
- Can mount to hundreds of instances across different AZ
- EFS share website files (WordPress)
- Only for Linux instances (POSIX)
- Higher price point than EBS
- Leverage Storage Tiers for cost savings