Unarchived Old EBS Snapshots

CloudZero has identified Amazon EBS snapshots that have been stored for an extended period in standard snapshot storage. These long-term snapshots are excellent candidates for EBS Snapshot Archive, which can reduce storage costs by up to 75% for snapshots that are rarely accessed.

What it does

This recommendation identifies EBS snapshots that are:

• Stored in standard EBS snapshot storage (not archived)
• Older than 90 days
• Incurring ongoing standard snapshot storage costs
• Good candidates for migration to EBS Snapshot Archive tier

EBS Snapshot Archive is designed for long-term retention of snapshots that are accessed infrequently—such as compliance archives, disaster recovery backups, or historical reference snapshots.

Why it matters

• Cost Savings: Snapshot Archive storage costs ~75% less than standard snapshot storage ($0.0125/GB-month vs $0.05/GB-month)
• Compliance: Maintain required long-term backups while dramatically reducing costs
• No Data Loss: Archives preserve complete snapshot data—they're just stored in a lower-cost tier
• Scalability: As snapshot storage grows over time, these savings compound

For example, a 1TB snapshot stored for a year:

• Standard storage: $600/year
• Archive storage: $150/year
• Savings: $450/year per TB

Recommended Actions

1. Review Snapshot Usage Patterns:

   • Identify snapshots that are retained for compliance or disaster recovery
   • Determine which snapshots are rarely or never restored
   • Confirm snapshots older than 90 days are good archival candidates
   • Verify that longer restore times (24-72 hours) are acceptable

2. Archive Eligible Snapshots:

   Via AWS Console:

   • Navigate to EC2 → Snapshots
   • Select snapshot(s) to archive
   • Actions → Archive snapshot

   Via AWS CLI:

   Bash

   aws ec2 modify-snapshot-tier \
     --snapshot-id snap-1234567890abcdef0 \
     --storage-tier archive

   Bulk Archive via CLI:

   Bash

   # List old snapshots
   aws ec2 describe-snapshots \
     --owner-ids self \
     --query 'Snapshots[?StartTime<=`2023-01-01`].SnapshotId' \
     --output text | \
   while read snap; do
     aws ec2 modify-snapshot-tier \
       --snapshot-id $snap \
       --storage-tier archive
   done

3. Implement Automated Archival Policies:

   • Use AWS Data Lifecycle Manager (DLM) to automatically archive snapshots based on age
   • Create lifecycle policies that:
     • Move snapshots to archive tier after 90 days
     • Delete archived snapshots after retention period expires
     • Apply to specific volumes by tags

4. Set Up Monitoring:

   • Track snapshot storage costs over time
   • Monitor archive vs standard storage distribution
   • Set CloudWatch alarms for unexpected snapshot growth
   • Review archived snapshots quarterly to confirm retention needs

5. Document Restore Process:

   • Document that archived snapshots take 24-72 hours to restore
   • Update disaster recovery runbooks with new restore timelines
   • Communicate changes to teams that may need to restore snapshots
   • Test restore process from archive to verify procedures

6. Review Retention Policies:

   • Evaluate whether all snapshots need to be retained
   • Delete snapshots that are no longer needed for compliance or recovery
   • Consider tiered retention: recent snapshots → archive → deletion

Cost Impact Calculation

The cost impact represents potential savings from archiving:

• Standard Storage: ~$0.05 per GB-month (varies by region)
• Archive Storage: ~$0.0125 per GB-month (75% cheaper)
• Savings: 75% of current standard snapshot storage costs

For a snapshot older than 90 days with $100/month in storage costs:

• Moving to archive saves: $75/month or $900/year

Important Considerations

Restore Times

• Standard snapshots: Instant availability for volume creation
• Archived snapshots: 24-72 hours to restore to standard tier before use
• Only archive snapshots where slow restore is acceptable

Use Cases for Archive

✅ Good candidates:

• Compliance/regulatory retention backups
• Long-term disaster recovery snapshots
• Historical reference snapshots
• End-of-month/quarter/year snapshots
• Snapshots of decommissioned resources

❌ Poor candidates:

• Snapshots for active disaster recovery (need fast restore)
• Recent snapshots (< 90 days old)
• Snapshots used for frequent testing or development
• Snapshots that may be needed quickly

Pricing Considerations

• Archive storage: $0.0125/GB-month (~$12.75/TB-month)
• Restore from archive: $0.03/GB retrieval charge (one-time when restoring)
• Standard storage: $0.05/GB-month (~$51.20/TB-month)

If you need to restore an archived snapshot frequently, the retrieval charges can offset savings.

Operational Impact

• No changes to snapshot permissions or sharing
• Snapshot IDs remain the same
• Tags and metadata are preserved
• Can restore to standard tier at any time (with 24-72 hour delay)

Best Practices

1. Age-Based Policy: Archive snapshots automatically after 90-180 days
2. Tag-Based Archival: Use tags to identify archive candidates (e.g., Archivable=true)
3. Test Restore Process: Periodically test restoring from archive to verify procedures
4. Lifecycle Management: Use DLM for automated archival and eventual deletion
5. Cost Tracking: Monitor savings from archival using Cost Explorer tags
6. Document Exceptions: Clearly identify snapshots that should never be archived