> ZFS-FUSE existed before ZoL did. The reason they moved to their SPL-based solution is because FUSE didn't want to make the required changes to support high pe

> ZFS-FUSE existed before ZoL did. The reason they moved to their SPL-based solution is because FUSE didn't want to make the required changes to support high performance file systems. These changes were made years later, but the developer of ZFS-FUSE disappeared, so they were never used. The FUSE v3 API further builds on that, and today, it's definitely possible to build a high-performance filesystem using FUSE. In fact, there are many examples of this in the wild: GlusterFS, Ceph, NTFS-3G, and so on. Today, there's absolutely _no_ reason ZFS would not sensibly work as high performance filesystem entirely from userspace. In fact, it still remains an open issue and a desirable target for ZoL: https://github.com/zfsonlinux/zfs/issues/8 https://github.com/zfsonlinux/zfs/issues/8