silverstripe-dms/docs/en/documents-on-the-filesystem.md

Documents on the Filesystem

While the DMS architecture allows for remote storage of files, the default implementation (the DMS class) stores them locally. Relations to pages and tags are persisted as many-many relationships through the SilverStripe ORM.

File locations in this implementation are structured into subfolders, in order to avoid exceeding filesystem limits. The file name is a composite based on its database ID and the original file name. The exact location shouldn't be relied on by custom logic, but rather retrieved through the API method DMSDocument::getLink.

Example:

dms-assets/
    0/
        1234~myfile.pdf
    1/
        2345~myotherfile.pdf