This is probably not relevant to Jepsen, and I don't know how similar to a distributed database distributed metadata in parallel filesystems look. Anyway, some

This is probably not relevant to Jepsen, and I don't know how similar to a distributed database distributed metadata in parallel filesystems look. Anyway, some of the tests for the Lustre PFS use Linux' fault injection system. Also, Linux documents specific support for NFS fault injection, which I know nothing about, and may or may not apply to pNFS. (It probably doesn't make it any more relevant or databased, but the OrangeFS PFS uses bdb or lmdb instances for the arbitrarily distributed metadata.)