[kev009]

I am curious about the inverse, using the dataset layer, to implement some higher level things like objects for an S3 compatible storage or pages directly for an RDBMS. I seem to remember hearing rumblings about that but it is hard to dredge up.

[p_l]

ZFS-Lustre operates this way.

Main issue with opening it further is lack of DMU-level userland API, especially given how syscall heavy it could get (and iouring might be locked out due to politics)

[magicalhippo]

There was some work on this presented at one of the OpenZFS summits. However it never got submitted. Not sure if it remains a private feature or if they hit some roadblocks.

In theory it should be a pretty good match considering internally ZFS is an object store.

[suprasam]

For RDBMS pages on object storage - you might be thinking of Neon.tech. They built a custom page server for PostgreSQL that stores pages directly on S3.