AWS Database Migration Service · Finder + automated fixer
DMS Remove Idle Instances
RemoveIdle Instances
Delete idle AWS DMS instances incurring hourly charges when not actively replicating. CloudFix identifies unused instances, backs up configs, and removes 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
AWS Database Migration Service (DMS) instances incur hourly costs whether or not they are used. This FF identifies DMS instances that have been idle for an extended period of time, creates a backup of each instance’s configuration, and terminates the instances.
AWS Database Migration Service (DMS) instances incur costs even when idle. This CloudFix feature identifies and terminates idle DMS instances to help you save on unnecessary expenses. It backs up the instance configuration before deletion, allowing for manual restoration if needed.
Overview
Problem Statement
AWS Database Migration Service (DMS) replication instances are charged on an hourly basis, regardless of whether they are actively migrating data. Instances left running but unused contribute to unnecessary AWS spending. Identifying and removing these idle instances is crucial for cost optimization.
Solution
CloudFix identifies DMS replication instances that have had no replication activity for an extended period. The Fixer then backs up the configurations of the instance and its associated tasks and terminates the idle DMS instance, eliminating ongoing costs.
AWS Services Affected
| Service | Icon |
|---|---|
| AWS Database Migration Service (DMS) |
 |
| Amazon S3 |
 |
How It Works
The finder uses your cost and usage data and DMS’s own task activity, read-only, to find replication instances that are still billing but have not run a migration task for an extended period. Each idle instance appears in your Recommendations for you to approve. Once approved, the fixer runs as an AWS Systems Manager Automation runbook in your own account: it saves the configuration of the instance and its associated replication tasks to Amazon S3 in your account, then deletes them. Every execution is logged.
FAQ
Q: What are the potential savings?
A: This feature saves nearly 100% of the cost associated with idle DMS instances. A negligible cost remains for storing the small configuration backup files in S3.
Q: Is rollback possible?
A: Yes, manual rollback is possible. You can run a rollback runbook that recreates the DMS instance and optionally restores its associated tasks from the saved configuration backups.
Q: Can CloudFix implement the fix automatically?
A: Yes, upon your approval, CloudFix can automatically execute the fix.
Q: Does this fix require downtime?
A: No, since the instances are already idle, deleting them does not cause downtime for active migration tasks.
Related Resources
- AWS DMS User Guide
- Amazon S3 User Guide
- Cost Optimization Strategies for DMS (AWS Blog)
- Clean up idle DMS instances (CloudFix Support)
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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