[dangoodmanUT]

If you actually bench it locally (local S3, actually writes to disk for "staged" operations), ZeroFS performs horrifically. Ceph blows it out of the water. I don't have the exact numbers, but when I was building a toy CoW distributed block device and filesystem I did a perf matrix, and ZeroFS (even with an hour of codex tuning it) was never within the same 1 or 2 orders of magnitude perf-wise.

Sure, Ceph isn't "S3-backed", but when you're talking about an actual filesystem or block device (the thing that does lots of small-IO), you care more about io-perf than sequential.

Large sequential jobs that everyone is targeting now (ie AI workloads) can use s3 directly just fine, because they don't have decades of code built on top of the filesystem.

[neverartful]

There are a couple of different ways of using Ceph with a filesystem: (1) CephFS, or (2) RBD (Ceph block device) volume mounted and then create filesystem on the mounted RBD volume. Historically, the RBD approach would likely have been the more common of the 2. Which of these 2 ways were you referring to?