S3 & EBS

Object storage and block storage

S3 (Simple Storage Service)

S3 is object storage — store unlimited files (up to 5TB each) organized in buckets. Highly durable (99.999999999% — 11 nines). Used for static assets, backups, data lakes, and static website hosting.

• Storage Classes: Standard (frequent access), IA (infrequent), Glacier (archive), Deep Archive
• Lifecycle Policies: auto-transition objects between storage classes based on age
• Versioning: keep all versions of an object for recovery
• Pre-signed URLs: temporary access to private objects
• Event notifications: trigger Lambda on upload/delete

EBS (Elastic Block Store)

• Block storage volumes attached to EC2 instances (like a hard drive)
• Types: gp3 (general SSD), io2 (high-performance SSD), st1 (throughput HDD)
• Snapshots: point-in-time backup, stored in S3
• Persists independently from EC2 instance lifecycle