While reviewing real-world cloud cost audits this week, the same infrastructure leak kept surfacing across multiple engineering teams: unattached EBS volumes and idle resources quietly inflating the monthly bill.

Where the Waste Hides

  • The Silent Accumulation: As Tim O'Brien recently highlighted, fifty abandoned 100 GB unattached EBS volumes cost roughly $500/month ($6,000/year). Clearing out forgotten storage isn't just a one-off cleanup—it requires continuous ownership tracking because unattached volumes persist indefinitely unless removed.
  • Orphaned Post-Termination Storage: Aman Maheshwari pointed out that in environments running hundreds of EC2 instances, attached EBS volumes often survive instance termination (if DeleteOnTermination was unset) and continue billing unnoticed.
  • The Extended Support Trap: Antonio Augusto Maguelniski shared a case where a client's AWS bill doubled without any new deployments—their RDS costs surged from $30 to $330/month simply because two PostgreSQL 12 instances slipped out of standard support into AWS Extended Support.

Auditing Unattached Volumes with Python & Boto3

Instead of manually clicking through region tabs in the AWS Console, you can query for detached volumes in available state across your infrastructure with a simple Boto3 inspection script:

import boto3 def audit_unattached_ebs(region='us-east-1'): ec2 = boto3.client('ec2', region_name=region) # Query volumes that are not attached to any running instance  response = ec2.describe_volumes( Filters=[{'Name': 'status', 'Values': ['available']}] ) orphaned_volumes = response.get('Volumes', []) print(f"[{region}] Found {len(orphaned_volumes)} unattached EBS volume(s):") total_wasted_gb = 0 for vol in orphaned_volumes: vol_id = vol['VolumeId'] size = vol['Size'] vol_type = vol['VolumeType'] total_wasted_gb += size print(f" - {vol_id} | {size} GiB ({vol_type}) | Created: {vol['CreateTime'].strftime('%Y-%m-%d')}") print(f"Total unattached storage: {total_wasted_gb} GiB") if __name__ == '__main__': audit_unattached_ebs('us-east-1')

Continuous FinOps Automation
Manually deleting disks risks wiping data that still needs an owner review, while leaving them alone guarantees continuous waste. Automated governance requires regular multi-account audits and programmatic reporting before executing snapshots or deletions.