AWS Storage Blog

New longer resource IDs for Amazon Elastic File System

To accommodate anticipated service growth in the future, Amazon Elastic File System (Amazon EFS) is migrating to longer format, 17-character resource IDs for its file systems and mount targets. You can opt into this change today, by using the Amazon EFS console, AWS Command Line Interface (CLI), or Amazon EFS API.

The switch-over to long IDs will not impact most of you. However, if you have a system that parses or stores resource IDs, you may be affected. I’m making you aware of the change so that you can schedule time to test your systems with the longer format. I recommend testing your systems and opting in to the longer ID format across all your accounts before the end of September 2021. Starting October 1, 2021, all newly created file systems and mount targets will receive the long format IDs.

The current format for IDs is a resource identifier followed by an 8-character string. The new format uses the same resource identifier followed by a 17-character string. For example, prior to implementing this change, your file system resource identifier looks something like “fs-1234abc0.” Beginning October 1, 2021, a new file system will be assigned an identifier like “fs-1234567890abcdef0.” You can continue using the 8-character IDs for your existing file system resources, which won’t change and will continue to be supported. Only new resources, created after opting in or after October 1, 2021, will receive the 17-character IDs.

In the remainder of this blog post, I cover opting in to the longer format IDs using the EFS console, AWS CLI, and Amazon EFS API.

Opting in to longer format ID using the Amazon EFS console

To opt into this change from the Amazon EFS console, select Settings from the left navigation pane. Next, choose Edit to make changes to the Amazon EFS settings:

Amazon EFS settings. Click on Edit to make changes to the Amazon EFS settings

Finally, enable the Long Resource IDs setting and choose Save:

Amazon EFS settings. Enable the Long Resource IDs setting and click Save

Opting in to longer format ID using the AWS CLI

To opt in using the AWS CLI, use the put-account-preferences command and specify the desired resource id type:

$ aws efs put-account-preferences--resource-id-type LONG_ID

Opting in to longer format ID using Amazon EFS API

To opt in from your own application code, make the PutAccountPreferences API call. For more information refer to the docs.


Starting October 1, 2021, Amazon EFS is migrating to 17-character resource IDs for newly created file systems and mount targets to accommodate for the service growth. You can opt into this change and test your system using the EFS console, EFS APIs, or AWS CLI. All existing resource IDs will remain unaffected by this change. Longer format IDs are available in all AWS Regions. For more information please refer to the Amazon EFS documentation. If you have questions, contact AWS Support on the community forums and via AWS Support.

Thanks for reading this blog post about Amazon EFS longer IDs. If you have any comments or questions, share them in the comments section.

Pratik Parekh

Pratik Parekh

Pratik Parekh is a Product Manager on the Amazon Elastic File System team. He is passionate about building solutions that help clients achieve their data protection goals. Prior to joining AWS, Pratik worked as a software engineer building financial products. He holds an MBA from Stern School of Business.