Amazon OpenSearch Service · Finder + automated fixer
OpenSearch Resize Volumes
ResizeVolumes
Resize overprovisioned EBS volumes on OpenSearch domains to reduce storage costs. CloudFix identifies domains with excess storage and right-sizes them.
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
Approve in Recommendations
It appears in your Recommendations view with what it would save. Approve the resources you choose. Nothing has changed yet.
Fixer
Runs in your account
The fixer runs as an AWS Systems Manager Automation runbook in your AWS account, and acts only on the resources you approved.
Record
Logs the execution
The Systems Manager execution is logged, so every change can be audited.
Finder role
Read-only. It can see resource metadata and usage. It can’t change anything.
Fixer role
A separate, minimal role that acts only on the resources you approved, through AWS Systems Manager.
Saves by
This Finder identifies OpenSearch domains that are over-provisioned in terms of attached storage volume size, which can lead to unnecessary costs. Since AWS charges premium pricing for OpenSearch EBS gp2 and gp3 volumes (35% and 52.5% more expensive than EC2 equivalents, respectively), right-sizing these volumes is a high-impact optimization opportunity.
Amazon OpenSearch domains with over-provisioned storage volumes incur unnecessary costs. This Finder/Fixer identifies OpenSearch domains with excessively large EBS volumes and intelligently resizes them based on actual usage patterns, while ensuring sufficient capacity for future growth. By automatically analyzing storage utilization trends and implementing optimal volume sizing, CloudFix helps you reduce costs while maintaining performance.
Overview
Problem Statement
OpenSearch domains often have storage volumes much larger than necessary, leading to significant waste in AWS spend. AWS charges premium pricing for OpenSearch EBS volumes (35% more for gp2 and 52.5% more for gp3 compared to regular EC2 volumes), making this over-provisioning particularly costly. Many organizations allocate excess storage as a precaution but never utilize it, paying for capacity that sits idle.
Solution
The OpenSearch Resize Volumes Finder/Fixer looks at how much of each domain’s storage is actually used and how fast it is growing, then recommends a smaller volume size that still leaves comfortable headroom for future growth. CloudFix then automates the resize, with built-in safeguards to protect ongoing performance and availability.
Benefits
By implementing this Finder/Fixer, you can:
- Reduce OpenSearch storage costs by 12% or more
- Eliminate unnecessary capacity while maintaining performance
- Implement data-driven storage sizing based on actual usage patterns
- Maintain appropriate safety margins with predictive capacity planning
- Apply consistent storage optimization across your AWS environments
AWS Services Affected
How It Works
The CloudFix Finder works read-only, using your cost and usage data and the storage metrics OpenSearch already reports to CloudWatch to find domains whose volumes are much larger than their current and projected needs. Each domain appears in your Recommendations with a suggested size, and nothing changes until you approve it.
Once approved, the Fixer runs as an AWS Systems Manager Automation runbook in your own account. It resizes the domain’s storage to the recommended size, then keeps watching free storage space and scales the volume back up automatically if usage grows faster than expected. Every execution is logged, and no downtime is required, though temporary performance impacts may occur during the resize.
FAQ
How does CloudFix decide a volume is over-provisioned?
CloudFix compares each domain’s allocated storage with how much it actually uses and how quickly that usage is growing. It only recommends a smaller size when that size still leaves a healthy buffer above projected needs and, for gp2 volumes, still supports the IOPS the domain requires.
How much can I expect to save with this optimization?
Typical savings from the OpenSearch Resize Volumes Finder/Fixer are 12% or more of your OpenSearch storage costs. Since AWS charges premium pricing for OpenSearch EBS volumes (35% more for gp2 and 52.5% more for gp3 compared to EC2 equivalents), the absolute savings can be substantial.
Is it possible to roll back if there are issues after resizing?
Yes. After the resize, CloudFix monitors free storage space and automatically resizes the volume back up if it runs low. If a cluster ever becomes unhealthy, it can also be restored manually from a snapshot.
Does this fix require downtime?
No, the resize operation does not require downtime. However, temporary performance degradation such as increased latency may occur during the resizing process. AWS temporarily increases the instance count during volume modification, which can put additional load on cluster master nodes. We recommend scheduling the fix during a maintenance window for production systems.
Will this affect my OpenSearch query performance?
The Finder/Fixer is designed to maintain performance by ensuring sufficient capacity. The recommended volume size keeps a healthy buffer above projected needs and accounts for IOPS requirements. After resizing, query performance should remain unchanged while still achieving cost savings.
What happens if my data grows faster than predicted after resizing?
CloudFix keeps monitoring free storage space after resizing. If usage grows faster than projected and free space runs low, an automatic rollback resizes the volume back up, so your cluster keeps adequate storage capacity.
Related Resources
- Optimize OpenSearch Domains with Over-Provisioned Storage
- Sizing Amazon OpenSearch Service domains
- Configuration changes in Amazon OpenSearch Service
Ready to start saving on AWS? See how much you could cut from your cloud bill with a free cost optimization assessment, or explore CloudFix automated Finder/Fixers that eliminate waste across 30+ AWS services.
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