I got to thinking, there is a lot of debate raging over whether ZFS or DFS (my tentative nickname for the alternative) is a better priority for development. I was previously on the ZFS camp, thinking a good on-disk file system which is gaining a lot of hype and adoption would be a very good bargaining chip in DragonFly's pile.
Now it just occurred to me we can have ZFS for the nominal price of supporting FUSE. It's not as fast as a pure kernel version, of course, but Matt says he wants userland file systems anyway and FUSE is a de-facto standard for that. Even NetBSD's puffs now has a 'refuse' compatibility kit. FreeBSD also has FUSE support. DragonFly can support FUSE by wrapping SYSLINK as is already planned, and this immediately gives it a lot of file systems currently beyond reach. FreeBSD has kernel support well on the way, and it seems to be ahead of the FUSE version. I don't know how useful this is to DragonFly (as far as being less work to port than the Solaris code, or being portable to userland). Not sure about the license issues of the FUSE ZFS, but purely pragmatically, it may be the 'right' thing to develop rather than try to port a kernel implementation into the DragonFly kernel. Like Matt said, even if DragonFly doesn't survive, a lot of its technology will, and developing things in the userland is precisely the way to ensure that's what happens. It seems almost obvious that this is how ZFS should be approached too, and it's already well on the way. --- Dmitri Nikulin Centre for Synchrotron Science Monash University Victoria 3800, Australia
