Amazon EFS Lifecycle Management: Files That Stay in Standard

So Amazon EFS lifecycle management is just the mechanism that moves files between different storage classes based on transition policies. Right. And EFS has specific storage classes. There is standard, infrequent access, and archive. Infrequent access, or IA, is cost optimized for data accessed only a few times each quarter.

Yeah. Archive is cost optimized for data accessed only a few times each year or less. But files actually stay in standard unless a policy moves them. Right. So a file system with no transition policy keeps old, untouched data in standard storage.

And it bills it at the standard storage rate. Transition time is based on when a file was last accessed in the standard storage class. Yeah. An internal timer tracks it. It is not the POSIX attributes you can see.

Right. So whenever a file in standard is accessed, the timer resets. Exactly. But metadata always stays in standard. So metadata operations such as listing a directory do not count as file access.

Right. And policies apply to the entire file system, not to a folder. Let's look at the specific policies. Okay. By default, files not accessed in standard for 30 days move to infrequent access.

Yeah. And by default, files not accessed in standard for 90 days move to archive. And that transition to archive can happen from standard or IA. Right. Now, by default, files accessed in IA or archive are not moved back to standard.

Right. The transition into standard policy on first access is an option for performance-sensitive workloads. For example, applications working with a large volume of small files. Exactly. And when they do move, transitions run at lower priority than your workload.

So the time they take varies with file size and workload. Transitioning millions of small files may take longer than fewer larger files of the same total size. Yeah. And while a file is transitioning, it is stored in standard and billed at the standard rate. Writes to files in IA or archive are first written to standard, and they are eligible to move after 24 hours.

Right. There is a free, read-only, source-available command line tool, pip install cloudcostwise, that runs on your machine against about 20 AWS services and sends nothing to CloudWise.