EBS snapshots are point-in-time backups of EBS volumes stored durably in Amazon S3. The first snapshot is a full copy, and subsequent snapshots are incremental — only the blocks that changed since the last snapshot are saved. Snapshots can be used to restore volumes, copy data across regions, or create AMIs.
An EBS snapshot captures the exact state of an EBS volume at a specific moment in time. Snapshots are stored in Amazon S3 (managed by AWS, not visible in your S3 console) and are highly durable (99.999999999% — 11 nines). Despite being incremental, each snapshot is a complete and independent restore point — you can always create a new volume from any snapshot without needing the previous ones.
Snapshot 1 (Full) — The first snapshot copies ALL blocks of the volume to S3. This takes the most time and storage.
Snapshot 2 (Incremental) — Only the blocks that changed since Snapshot 1 are saved. Unchanged blocks are referenced from Snapshot 1.
Snapshot 3 (Incremental) — Only the blocks that changed since Snapshot 2 are saved.
Restoration — When restoring from Snapshot 3, AWS assembles the full volume by combining data from all referenced snapshots automatically. No manual chain management needed.
Deletion — Deleting an intermediate snapshot does NOT cause data loss. AWS automatically moves referenced blocks to adjacent snapshots.
Cross-AZ restore — create a new EBS volume from a snapshot in ANY Availability Zone within the same region
Cross-region copy — copy snapshots to other AWS regions for disaster recovery
Cross-account sharing — share snapshots with specific AWS accounts or make them public
AMI creation — create a new Amazon Machine Image from a snapshot of a root volume
Encryption inheritance — if you create a volume from an encrypted snapshot, the new volume is automatically encrypted
Data Lifecycle Manager (DLM) — automate snapshot creation, retention, and deletion using policies
Take snapshots of idle or quiesced volumes for consistency — for databases, flush and freeze I/O before snapshotting
Use AWS Data Lifecycle Manager (DLM) to automate daily/weekly snapshots and automatic cleanup
Copy critical snapshots to a different region for disaster recovery
Tag snapshots with meaningful metadata: environment, application, date, owner
Monitor snapshot costs — incremental snapshots are cost-effective, but frequent full-change workloads can accumulate costs
Use Snapshot Archive for long-term retention at 75% lower cost (with a retrieval time of 24–72 hours)
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