Suboptimal RDS Instance Storage Type

Service Category

Database

Cloud Provider

AWS

Service Name

AWS RDS

Inefficiency Type

Inefficient Configuration

Explanation

This inefficiency occurs when an RDS instance uses a high-cost storage type such as io1 or io2 but does not require the performance benefits it provides. In many cases, provisioned IOPS are set at or below the free baseline included with gp3 (3,000 IOPS and 125 MB/s). In such scenarios, continuing to use provisioned IOPS storage results in elevated cost with no functional advantage. These misconfigurations often persist due to legacy templates, default settings, or a lack of periodic review.

Relevant Billing Model

RDS storage is billed per GB-month based on the storage type selected. Premium options like io1 and io2 charge separately for provisioned IOPS, while general-purpose types like gp3 include baseline IOPS and throughput at no extra cost. Overprovisioning or selecting the wrong storage tier leads to unnecessary spend.

Detection

Identify RDS instances using high-cost storage types (e.g., io1, io2)
Review IOPS and throughput metrics to assess whether provisioned performance is being fully utilized
Evaluate whether current workloads would meet SLAs with a general-purpose alternative like gp3
Confirm with application owners whether the selected storage type is still required

Remediation

If the provisioned IOPS are within the gp3 baseline, migrate to gp3 to reduce costs without impacting performance. Storage type changes may require a snapshot restore or be applied during a maintenance window, depending on the database engine and configuration. Update infrastructure templates and provisioning logic to default to gp3 when appropriate.

Relevant Documentation