# Inactive and unmounted EFS file system | Cloud Efficiency Hub Canonical: https://www.pointfive.co/efficiency-hub/inefficiencies/inactive-and-unmounted-efs-file-system EFS file systems that are no longer attached to any running services - such as EC2 instances or Lambda functions - continue to incur storage charges. By: Shireen Maini Updated: 2026-09-28 [Cloud Efficiency Hub](https://www.pointfive.co/efficiency-hub) # Inactive and Unmounted EFS File System The short version EFS file systems that are no longer attached to any running services - such as EC2 instances or Lambda functions - continue to incur storage charges. [Shireen Maini](https://www.linkedin.com/in/shireen-maini/) DevOps Team Lead @ BroadPeak Partners AWS service [AWS EFS](https://www.pointfive.co/efficiency-hub/cloud-services/aws-efs) Category [Storage](https://www.pointfive.co/efficiency-hub/service-category/storage) Reference CER-0018 Type Idle or Unused Resource ## Explanation Why the waste happens and who it affects. This often occurs after workloads are decommissioned but the file system is left behind. A quick indicator of this state is when the EFS file system has no mount targets configured. Without active usage or connection, these orphaned file systems represent pure cost with no functional value. Like EBS volumes, EFS file systems are billed for stored data whether or not anything is mounted, making it easy for unused resources to go unnoticed. ## Billing model The pricing dimensions that drive this cost. EFS is billed based on: - Total data stored (per GB/month) - Storage class (Standard, Infrequent Access, or Archive, with data moved to IA or Archive by lifecycle policies) - Throughput: Elastic throughput (the default mode) bills per GB of data transferred, while Provisioned throughput bills for throughput provisioned above the baseline included with Standard storage Even when unmounted, EFS continues to accrue storage cost until deleted. ## How to detect 5 checks to find it in your estate. - Identify EFS file systems with no mount targets present - Exclude file systems that are replication destinations (check DescribeReplicationConfigurations); Amazon EFS creates destination file systems without mount targets by design - Check for file systems with no recent read/write activity over a representative time window - Correlate with decommissioned EC2 instances or workloads that previously used the file system - Confirm with workload owners whether the data is still required or can be deleted ## How to fix 3 ways to remove the waste. - Delete EFS file systems that are no longer in use and have no attached mount targets - If data must be retained, consider exporting it to a lower-cost storage service (e.g., S3 Glacier) before deletion - Establish periodic audits to identify and clean up orphaned file systems ## Documentation Vendor references for pricing and configuration. - [Amazon EFS Pricing aws.amazon.com](https://aws.amazon.com/efs/pricing/) - [Managing mount targets docs.aws.amazon.com](https://docs.aws.amazon.com/efs/latest/ug/accessing-fs.html) - [Configuring replication to new EFS file system docs.aws.amazon.com](https://docs.aws.amazon.com/efs/latest/ug/create-replication.html) ## Related inefficiencies [Browse the library](https://www.pointfive.co/efficiency-hub) - AWS EFS CER-0198 ### [Suboptimal Use of EFS Storage Classes](https://www.pointfive.co/efficiency-hub/inefficiencies/suboptimal-use-of-efs-storage-classes) Many organizations default to storing all EFS data in the Standard class, regardless of how frequently data is accessed. This results in inefficient spend for workloads with significant portions of data that are rarely read. EFS IA and... Storage - AWS EFS CER-0123 ### [Overprovisioned Throughput in EFS](https://www.pointfive.co/efficiency-hub/inefficiencies/overprovisioned-throughput-in-efs) When file systems are launched with Provisioned Throughput, teams often overestimate future demand - especially in environments cloned from production or sized "just to be safe." Over time, many workloads consume far less throughput than... Storage - AWS EFS CER-0143 ### [Missing Lifecycle Policy on Replicated EFS File System](https://www.pointfive.co/efficiency-hub/inefficiencies/missing-lifecycle-policy-on-replicated-efs-file-system) When replicating an EFS file system across AWS regions (e.g., for disaster recovery), the destination file system does not automatically inherit the source's lifecycle policy. As a result, files replicated to the destination will remain in... Storage --- Source: the public page above. Product screenshots and illustrative interfaces are examples, not live customer data.