Historically, Fedora fulfilled its promise of married the concepts of persistence and durability by choosing transparent forms of persistence (e.g. .  Fedora 3 wrote human-readable XML ) and using them in ways that systems outside to disk, which could be indexed and manipulated by the Fedora repository software but which systems beyond the repository could also readily penetrate if needed. Transparency in support of durability is as valid a principle as ever, but there is a weakness to itthis strategy: transparent forms of persistence are not performant. What's moreAdditionally, many users didn't particularly care for that principle, but they were still stuck paying incurred the performance costs associated with it.  So in the move from Fedora 3 to Fedora 4, we shifted we divorced the two concepts, moving responsibility for transparent persistence away from the core repository software. If you'd like to maintain some simple, human-readable form of your repository, that's fine, but you need to support that with an integration around the core. The  

The operational form of persistence used by the core repository component itself - essentially a specially designed table and index within a relational database system for metadata and a curated filesystem structure for binaries - is not meant to be manipulated directly by a human except in the most unusual situations, it. It's meant designed, instead, for use by the software to provide speedy service at as performant a response as possible for the repository's defined API. You might compare this to the use of database software. You don't expect to directly manipulate database indexes, and   Comparison to a traditional RDBMS is appropriate: if you are concerned for the durability of your data in the a relational database, you take export/dump backups in a transparent format to disk and use _those_ to ensure durability.  You would never attempt to run your system based exclusively on a disk backup/dump sitting on disk.  The Backup procedure discussed on this page serializes the metadata and binaries from persistence layer to disk principally to support the Restore procedure into a repository-specific persistence layer.

If you like to maintain transparent persistence - an export that is a simple and human-readable form of your repository - this is supported with an integration around the core.
An analogy: you may expect your bank to provide downloadable images for any checks you write, but you don't expect them to use those images to run their accounting software. 

POST /rest/fcr:backup

> optional POST body pointing to the local filesystem backup directory to which the export will be written.