How to run Minio in legacy FS mode again

Has your bare-metal / single-node Minio deployment started creating .xl.meta files instead of the files you actually intended to transfer? This is happening because of a significant update / deprecation in June 2022.

Here's a workaround to restore the previous behaviour..

Background

Starting with RELEASE.2022-06-02T02-11-04Z, MinIO implements a zero-parity erasure coded backend for single-node single-drive deployments. This feature allows access to erasure coding dependent features without the requirement of multiple drives..

.xl.meta instead of files

This unfortunately breaks expected behavior for a large number of existing users, since Minio can no longer be used to provide an S3-compatible layer to transfer files to later be consumed via typical POSIX access.

Workaround to revert Minio to legacy fs mode

Note that the docs re pre-existing data indicate that in the case of Existing filesystem folders, files, and MinIO backend data, then MinIO resumes in the legacy filesystem (“Standalone”) mode with no erasure-coding features.

So a simple workaround is to create the following format.json in /path-to-existing-data/.minio.sys/:

{"version":"1","format":"fs","id":"avoid-going-into-snsd-mode-legacy-is-fine-with-me","fs":{"version":"2"}}

When Minio starts, it recognizes this as "existing" (above), and happily starts in legacy mode! ??