Idle EFS file systems have no or near-zero read/write throughput over the last 30 days but still incur storage charges. This is different from missing lifecycle policy, where the file system may still be actively used but all data stays in Standard storage.
Before you delete
- Confirm no EC2 instances, ECS tasks, Lambda functions, or other workloads still mount this file system.
- Check mount targets in each VPC — active mount targets mean something may still depend on this EFS.
- Create an AWS Backup recovery point first if the data might be needed later.
Deleting an idle file system
All mount targets must be removed before the file system itself can be deleted. Paid plans include remediation scripts that list mount targets, delete them, and then delete the file system.
Savings equal 100% of ongoing storage charges for the file system — Parsivex estimates this at the Standard storage rate ($0.30/GB-month) multiplied by total stored size.
AWS EFS delete-file-system does not support --dry-run — review commands carefully before running them.
What triggers this finding
An EFS file system with no or near-zero read/write throughput over the lookback window.
Typical fix
Delete the file system if no workloads mount it. Confirm EC2 instances and Lambda functions no longer depend on it.
Example savings
100% of storage charges — scales with stored data (e.g. $0.30/GB-month for Standard storage).
See also: Severity and savings estimates for how Parsivex calculates figures on your report.