AWS Backup Cost Analysis

The Problem

An enterprise workload’s AWS Backup costs were growing steadily month-over-month. The team knew snapshots were accumulating but didn’t have visibility into:

• Why costs were increasing at that rate
• Whether the backup configuration matched actual recovery needs
• What steady-state costs would look like
• How to optimize without compromising recovery capabilities

The Solution

Performed a comprehensive cost analysis that revealed:

• 57 recovery points per volume from overlapping daily/weekly/monthly/yearly backups
• No cold storage tiering — all backups stored at warm tier pricing ($0.05/GB vs $0.0125/GB)
• ~$38,000/year potential savings by enabling cold storage transitions

How It Works

Current Cost Breakdown

Workload	Monthly Cost	Annual Cost
Production	~$2,300	~$27,600
Secondary	~$2,660	~$31,900
Total	~$4,960	~$59,500

Backup Plan Configuration

The backup plans create 57 recovery points per volume:

Backup Type	Frequency	Retention	Recovery Points
Daily	1/day	30 days	30
Weekly	1/week	90 days	~13
Monthly	1/month	365 days	12
Yearly	1/year	730 days	2
Total			~57

Steady State Formula

Developed a formula to calculate expected storage at steady state:

Steady State Storage = Volume Size × Multiplier

Where Multiplier = 1 + (Change Rate × (Recovery Points - 1))

Example:
- Volume Size: 500 GB
- Change Rate: 5%
- Recovery Points: 57
- Multiplier: 1 + (0.05 × 56) = 3.8
- Steady State: 500 GB × 3.8 = 1,900 GB per volume

The Fix: Cold Storage Tiering

Current configuration (no cold storage):

{
  "DeleteAfterDays": 365
}

Recommended configuration:

{
  "MoveToColdStorageAfterDays": 14,
  "DeleteAfterDays": 365
}

Cost Impact

Scenario	Monthly Cost	Annual Cost
Current (all warm)	~$4,960	~$59,500
With cold storage	~$1,500-1,800	~$18,000-21,600
Potential Savings	~$3,200/month	~$38,000/year

What I Learned

• Data analysis with AI is powerful — Extracting and analyzing Excel data, even when tools couldn’t read the file directly, was possible by extracting XML from the xlsx archive
• Proactive cost modeling is key — Many organizations don’t calculate steady-state costs before implementing their backup strategy
• Quick wins exist — Cold storage tiering is a configuration change that can save 60-75% on long-term backups
• Visualization helps — Snapshot growth charts immediately reveal accumulation patterns

Do It Yourself

Key Takeaways

• Cold storage transitions are the biggest lever — moving backups older than 14-30 days to cold storage saves 60-75% on long-term retention without impacting recovery speed for recent backups.
• 57 recovery points is likely overkill — most workloads don’t need overlapping daily, weekly, monthly, and yearly backups. Validate RPO/RTO requirements before configuring retention policies.
• Steady-state cost modeling prevents surprises — use the formula Steady State = Volume Size × (1 + Change Rate × (Recovery Points - 1)) to project costs before implementing a backup plan.

Try It Now

1. Audit your current backup plans — run aws backup list-backup-plans and aws backup get-backup-plan --backup-plan-id <id> to see retention policies and lifecycle rules. Look for plans with no MoveToColdStorageAfterDays configuration.
2. Calculate your current recovery points — sum daily (30) + weekly (~13) + monthly (12) + yearly (2) retention periods. If total > 40, you’re likely over-retaining.
3. Enable cold storage tiering — update backup plans to transition backups to cold storage after 14-30 days. AWS Backup documentation: Lifecycle to Cold Storage
4. Set up cost alerts — create a CloudWatch alarm on the BackupStorage metric with a monthly threshold. Tutorial: CloudWatch Alarms for AWS Backup
5. Use AWS Backup Audit Manager — enable compliance checks for backup lifecycle policies. This automatically flags backups not using cold storage. Audit Manager setup guide

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