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Description

This policy identifies AWS EBS volumes of type gp3, io1, and io2 that are underutilized based on their I/O operations over a 30-day period. A volume is considered underutilized if it is provisioned for high performance but exhibits low actual usage, indicating an opportunity for cost optimization.

Criteria and Thresholds:

  • gp3 volumes:

    • Volumes provisioned with IOPS above the free baseline of 3,000.
    • Maximum theoretical operations per month for a 3,000 IOPS volume is 7,776,000,000 operations (calculated as 3,000 IOPS × 86,400 seconds/day × 30 days).
    • The threshold of 1,944,000,000 operations corresponds to one-quarter of the maximum, serving as a marker for low utilization.
    • Volumes below this threshold are considered good candidates to be downsized to the 3,000 IOPS baseline.

  • io1 and io2 volumes:

    • Minimum provisioned IOPS for these volumes is 100 IOPS.
    • Maximum theoretical operations per month for a 100 IOPS volume is 259,200,000 operations (100 IOPS × 86,400 seconds/day × 30 days).
    • The threshold of 64,800,000 operations represents one-quarter of this maximum, indicating underutilization.
    • Volumes below this threshold are good candidates to be downsized to better match workload requirements.

Rationale​

High-performance EBS volumes (io1, io2) or gp3 volumes provisioned above the baseline IOPS result in unnecessary expenditure when being underutilized. By identifying such volumes, organizations can analyze workload patterns and rightsize them by adjusting size, type, or provisioned IOPS to better align with actual performance requirements.

Impact​

Before modifying any volume, it is essential to review historical performance data to avoid potential performance degradation during traffic spikes or peak workloads.

Audit​

An AWS EBS Volume is flagged as INCOMPLIANT if it meets either of the following conditions:

  1. The volume Type is gp3, provisioned IOPS exceed 3,000, and CloudWatch: Write OPS Sum, 30-Day and CloudWatch: Read OPS Sum, 30-Day metrics are both less than 1,944,000,000 operations.
  2. The volume type is io1 or io2, and the CloudWatch: IOPS Sum, 30-Day metric is less than 64,800,000 operations.

A volume is considered INAPPLICABLE if any of the following conditions are met:

  • The volume is not attached to an EC2 instance.
  • The volume was created or attached less than 30 days ago.
  • The CloudWatch: Write OPS Sum, 30-Day and CloudWatch: Read OPS Sum, 30-Day metrics are zero or null, and the volume is evaluated by the AWS EBS Volume is Idle policy.
  • The volume Type is not gp3, io1, or io2.