Amazon RDS · Finder + guided fix

RDS Rightsize Storage

RightsizeStorage

Right-size RDS database storage volumes to eliminate overprovisioned space. CloudFix identifies RDS instances with excess storage for optimization.

Guided fix
Effort: Advanced
Action: Resize
Amazon RDS

What happens, in order.

Finder · read-only
Finds the opportunity
Scans your connected accounts with a read-only role. It can see resource metadata and usage; it can’t change anything.
You
Review in Recommendations
It appears in your Recommendations view with what it would save.
Guided fix
You make the change
You apply it yourself, following the fix’s step-by-step instructions; the write-up below explains it.

Finder role

Read-only. It can see resource metadata and usage. It can’t change anything.

Fixer role

Not used here: this one is a guided fix, so the change is yours to make.

Saves by

CloudFix identifies opportunities to reduce costs by resizing RDS storage volumes without impacting performance. It targets volumes where the allocated storage far exceeds what the database needs, while leaving headroom for growth. Recommendations include switching to GP3 where applicable, optimizing for cost without compromising on performance or availability.

Amazon RDS databases often have storage volumes that are significantly larger than necessary, resulting in wasted cloud spend. The RDS Optimize Storage Finder identifies opportunities to right-size your RDS storage volumes without impacting performance or future growth requirements. By implementing these recommendations, you can reduce your RDS storage costs while maintaining appropriate capacity for your database workloads.

Overview

Problem Statement

Amazon RDS storage provisioning often follows a cautious approach: database administrators allocate more space than immediately needed to accommodate future growth, avoid capacity issues, and minimize maintenance windows. However, this proactive provisioning frequently results in significant over-allocation, with many databases using only a small fraction of their allocated storage over extended periods.

This over-provisioning creates several challenges:

Unnecessary costs for unused storage capacity
For GP2 volumes, excessive IOPS allocation (since IOPS scale with volume size)
Difficulty in accurately forecasting and controlling database infrastructure costs
Sunk capital in resources that provide no operational benefit

Unlike compute resources which can be easily downsized, RDS doesn’t natively support reducing storage allocation, making optimization more complex and often overlooked.

Solution

The RDS Optimize Storage Finder identifies databases with significantly over-provisioned storage volumes and recommends storage configurations that cut cost without compromising performance or future capacity needs.

Key aspects of the solution include:

Identifying instances where allocated storage substantially exceeds actual usage
Analyzing storage type (GP2, GP3, IO1) to recommend the most cost-effective configuration
Ensuring adequate IOPS for performance-sensitive workloads
Recommending storage autoscaling to automatically handle future growth
Leaving headroom for growth after optimization

While RDS doesn’t allow direct storage downsizing, the Finder provides detailed guidance on creating a new instance with optimized storage and migrating your data, enabling significant long-term cost savings.

Benefits

By implementing the RDS Optimize Storage recommendations, you can achieve:

Substantial cost savings (typically 30-40%) on RDS storage expenses
Improved cost efficiency through optimized storage-to-usage ratios
Enhanced performance when migrating from GP2 to GP3 storage
Better alignment of resources with actual requirements
Simplified capacity management with autoscaling enabled
Greater visibility into database storage utilization

AWS Services Affected

Amazon RDS

How It Works

The RDS Optimize Storage Finder works read-only from your cost and usage data and RDS’s own storage and performance metrics to find databases whose allocated storage far exceeds what they use. Each opportunity appears in your CloudFix Recommendations with the current allocation, a recommended size and storage type, and the projected annual savings. Because Amazon RDS can’t shrink allocated storage in place, this is a guided change: your team creates a new instance with the recommended storage (switching to GP3 where it makes sense and enabling storage autoscaling), migrates the data, and cuts over. For production databases, AWS Database Migration Service (DMS) helps keep downtime to a minimum.

FAQ

Can Amazon RDS storage be reduced directly?

No, Amazon RDS doesn’t support direct reduction of allocated storage. This limitation stems from the underlying Amazon EBS volumes, which can only increase in size, not decrease. The only way to reduce storage is to create a new RDS instance with optimized storage and migrate your data.

How does CloudFix ensure that the recommended storage size is sufficient?

CloudFix bases each recommendation on your database’s actual storage usage over time and leaves headroom for growth. It also recommends enabling storage autoscaling, which automatically increases storage when needed, preventing capacity issues as your database grows.

Will reducing storage impact my database performance?

For GP2 storage types, performance (IOPS) is directly tied to volume size. CloudFix takes this into consideration and ensures that recommended optimizations won’t reduce available IOPS below your workload requirements. In many cases, CloudFix recommends migrating to GP3, which decouples performance from storage size, allowing you to maintain or improve performance even with smaller volumes.

What is the difference between GP2 and GP3 storage, and why might CloudFix recommend switching?

GP2 storage allocates IOPS based on volume size (3 IOPS per GB), while GP3 allows independent provisioning of storage size, IOPS, and throughput. GP3 is generally 20% cheaper than GP2 for the same storage capacity and offers more predictable performance. CloudFix may recommend switching to GP3 when it provides the same or better performance at a lower cost.

How does RDS storage autoscaling work?

RDS storage autoscaling automatically increases your allocated storage when free space falls below 10% for at least 5 minutes. It’s designed to prevent storage-full scenarios that could impact database availability. Autoscaling increments are either 10% of current size, 5 GB, or projected 7-hour growth, whichever is largest. You configure a maximum threshold to control costs, and autoscaling never exceeds this limit.

What is the typical migration downtime when implementing these recommendations?

Downtime varies based on database size, migration method, and engine type. Small databases using dump/restore methods might require minutes to hours of downtime. Using AWS DMS with change data capture (CDC) can reduce downtime to seconds or minutes for the final cutover. For critical systems, you can implement replication-based approaches with minimal downtime, though these require more complex setup and testing.

Can CloudFix automatically implement these storage optimizations?

No, RDS Optimize Storage is a Finder-only feature that requires manual implementation. Since optimizing RDS storage involves creating new instances and migrating data (potentially impacting production systems), CloudFix provides recommendations and guidance but leaves the implementation to your database team to ensure proper testing and validation.

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What happens, in order.

Finds the opportunity

Review in Recommendations

You make the change