Inactive RDS Cluster

Service Category

Database

Cloud Provider

AWS

Service Name

AWS RDS

Inefficiency Type

Unused Resource

Explanation

This inefficiency occurs when an RDS cluster remains provisioned but is no longer serving any workloads and has no active database connections. Unlike underutilized resources, these clusters are completely idle—showing no query activity, background processing, or usage over time. They often persist in dev, staging, or legacy environments where the workload has been retired or moved, yet the cluster remains active and continues to generate ongoing compute and storage costs.

Relevant Billing Model

RDS clusters are billed per hour based on the instance types used for each node (primary and replicas), along with additional charges for storage, I/O, backups, monitoring, and data transfer. Charges continue to accrue even if the cluster is idle or not serving traffic.

Detection

Identify RDS clusters with no active connections or query activity during the lookback period
Confirm whether the cluster is receiving any traffic from applications or internal services
Check for sustained low or zero CPU utilization, network throughput, and read/write IOPS
Evaluate whether the cluster is part of a dev/test environment that is no longer in use
Consult application and database owners to confirm that the cluster is no longer needed

Remediation

Decommission the RDS cluster after confirming it is no longer in use. Take a final snapshot if the data may be needed later, and ensure that associated backups and read replicas are also deleted if not required. Incorporate regular reviews of cluster activity to identify and clean up idle infrastructure.

Relevant Documentation