Summary: https://www.udemy.com/course/aws-certified-cloud-practitioner-new/learn/lecture/20260618

• Contents:

Storing EC2 Data

• Any data stored by an EC2 instance is stored in either:
  • Internal block storage in the EC2 host (Instance Store) - ephemeral
  • External storage over the NW - persistent
    • Block stores: EBS volumes
    • File stores: EFS drives or FSx file systems
• An EC2 instance ALWAYS requires an attached boot/root volume
  • Boot volume is almost always an EBS volume
  • Boot volume contains data needed for an instance OS to launch/boot
  • OS-level data stored in boot volume by default
  • Instance can have additional storage volumes attached to it

EC2 Instance Store

Ref: https://www.udemy.com/course/aws-certified-cloud-practitioner-new/learn/lecture/20055816

• 🔧 High performance HW disk hosted in an EC2
  • ❗ Since it's in the same HW as the instance, it's really, really fast!
    • High speed, throughput, and Input/Output Operations per Second (IOPS), low latency
• ‼️ Ephemeral storage!!
  • Lost if our instance is stopped or terminated!! → this usually implies deleting the instance from the EC2 host, which in turn means losing the instance store volume
• ❗ Not all EC2 instances support instance store volumes!

Amazon Elastic Block Store (EBS)

Ref: https://www.udemy.com/course/aws-certified-cloud-practitioner-new/learn/lecture/20055762

• 🔧 Persistent Block Storage volumes over the NW
  • 💡 Like a USB pendrive/stick with extra storage for your machine (instance), accessible over the NW
• Characteristics of EBS volumes
  • ❗ EBS volumes tied to ONE AZ!
  • An instance can have 0+ EBS volumes (it normally has at least 1 - the boot volume)
  • An EBS volume is normally attached to 0-1 instances
  • ❗ Storage over the NW → has some latency, less performant than HW storage like EC2 instance store
  • Can persist after instance termination
    • EBS boot volumes are by default terminated with EC2 instance termination, other EBS volumes persist by default after EC2 instance termination
• EBS Snapshots = backups of an EBS volume, stored in S3
  • A new EBS volume can be restored from a snapshot/backup
  • Restores can happen cross-AZ and cross-region

EC2 Amazon Machine Image (AMI)