[OpenIndiana-discuss] Illumos UFS vs FreeBSD UFS?

[Michael Schuster]

Hi,

On Sat, Jan 23, 2021, 08:23 Chris <oidev at bsdos.info> wrote:

> On 2021-01-22 23:17, Chris wrote:
> > On 2021-01-22 22:58, Hung Nguyen Gia via openindiana-discuss wrote:
> >> Are they compatible? Could I use UFS for data exchange purpose?
> >>
> >> UFS is available on all BSDs, including one doesn't support ZFS. So
> it's a
> >> better
> >> portable FS than ZFS.
> >>
> >> But I'm a bit pessimistic, because each BSD's UFS is different to the
> >> other. e.g:
> >> FreeBSD's UFS2 doesn't mountable under DragonflyBSD, which only
> supports
> >> UFS1.
> > FWIW Dragonfly was forked to show off the hammer filesystem he created.
> As
> > such,
> > not much interest in keeping ffs in sync.
> > Truth is; ffs was created by BSD. Anyway. I'm betting the differences,
> if
> > any, are
> > minimal. It would be trivial to experiment on a couple USB sticks if you
> > don't have
> > a couple spare platters.
> >
> > Good question. Glad you brought it up.
> >>
> >> So I don't expect much.
> >>
> >> BTW, our UFS is UFS2 or UFS1 or something else?
> > _technically_ it's ffs v ffs2. Hope that helps. :-)
> Hmm... well the man pages are not forthcoming on this.
> Well, as I remember the early days, it was initially called
> ffs -- Fast File System. The updates garnered the title ffs2.
> I'll need to dig into my archives.
>


I wouldn't expect too much in ways of compatibility of the on-disk format
between the two: FreeBSD introduced soft updates, whereas Solaris
introduced logging support (among other things).
The authority on FreeBSD's ufs implementation is Kirk McKusick and his
"design and implementation of the FreeBSD operating system"; for Solaris
ufs, I'd wait for people to come forth :)

HTH
Michael

>
> --Chris
> >
> >>
> >> Please let me know. Thanks.
> >>
>
> --
> ~10yrs a FreeBSD maintainer of ~160 ports
> ~40yrs of UNIX
>
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