No doubt Facebook considers theirs a competitive advantage, but I'm kind of surprised there isn't a reasonably robust OSS erasure-coding based object store available in 2019. Maybe LizardFS?
Ceph has an object-store interface (which might still account for the majority of its usage) and some people I used to work with on Gluster are now at Minio, so those are the two I'd look at if I needed something in that space.
