Ref: https://learn.cantrill.io/courses/1820301/lectures/41301325

• Summary
• Contents:

💡 Learn all these facts and numbers for the exam, they're important!

Common Requirements for Storing EC2 Data

• ‼️ Persistent storage → Avoid instance store!!
  • First and foremost criterion!
  • Many ways where instance store data can be lost
  • Corollary: storage isolated from instance lifecycle? → Avoid instance store!
• Resilient storage → Avoid instance store (in general)
  • Again, many ways where instance store data can be lost
  • EBS has AZ resiliency and also possibility of S3 snapshots → pretty good resiliency
  • Exception: App supports built-in replication
    • Possible to use lots of instance store volumes on lots of instances to enjoy performance benefits without the negative risk of non-resiliency
• High performance → depends
  • Up to a point, both EBS and Instance Store can provide high performance
  • EBS max performance numbers:
    • ❗ Remember: these are numbers for larger instance types!
    • GP2/3: up to 16k IOPS per volume
    • IO1/2: up to 64k IOPS per volume
      • IO2 Block Express: up to 256k IOPS per volume
  • ❗ Possible to create a RAID0 set of EBS volumes to combine performances… but remember there's a limit per EC2 instance!!!
    • Maximum IOPS for EBS volumes per EC2 instance = 260k IOPS
  • Super high performance (> 260k IOPS) → probably instance store
    • ❗ Just make sure app can tolerate non-persistent storage!
• Cost → default to instance store (it's often included with EC2 instance price)
  • If need to use EBS → ST1 or SC1 are cheapest
    • Throughput or streaming → ST1
    • ‼️ If you need a boot volume → Can NOT use ST1 or SC1!