[binarycrusader]

ZFS isn't clustered

The ZFS storage appliance offers clustered configurations: https://www.oracle.com/storage/nas/index.html

It's unclear what your requirements are when stating "clustered".

and has no concept of HSM, so migrating hot blocks from NVMe to SSD then disk and tape isn't an option

Oracle HSM integrates with ZFS:

https://www.oracle.com/storage/tape-storage/hierarchical-sto...

Also stuff around disk rebuilding is still pretty old. Modern FSs can detect a failed disk and rebuild the array in minutes based on FEC and even distribution of data.

ZFS can detect a failed disk and rebuild in minutes as well depending on storage and system speed, etc. so I'm wondering what you're referring to?