Matt Dillon, of well deserved FreeBSD and DragonFlyBSD fame, has floated a proposal for a new filesystem. Some have called it a cluster filesystem, which seems a bit odd to me since … well, there doesn’t seem to be any actual cluster functionality involved. There’s some stuff about replication, but that seems more oriented toward slow links and disconnected nodes. There’s nothing about issues like coherency and latency reduction and access control across systems and split-brain scenarios and scaling across storage systems … i.e. the kinds of issues that require the most design effort for an actual cluster filesystem. So maybe it’s a “cluster filesystem” not in the sense of providing cluster functionality itself but instead by being more compatible with other cluster software? That would mean failing over better or faster than other filesystems, or perhaps having some extra hooks to exchange cluster-relevant events, but none of those features seem to be there either.

Coda did disconnected clients two decades ago, and its descendants are still going strong. Many projects and products out there do replication, often including extra functionality such as WAN optimization and CDP as well. Where’s the novelty? How is Yet Another Local Filesystem, with not even as robust a feature set as ZFS but with basic replication tacked on, the best use of anyone’s time and energy? If you’re going to all that trouble, Matt, do something more ambitious. I know you have the talent for it.