Trouble with snapshots

[Cyrus Rahman]

>  > This is happening on a system set up with journaled ufs filesystems,
>  > so that may be part of the problem.  The system is running amd64
>  > with an Intel Q6600.
>
>  I thought gjournal and soft updates were supposed to be mutually
>  exclusive (the latter is required for UFS snapshots).  Anyway, even if
>  they are supposed to work together this interaction is almost certainly
>  the cause.

I actually think that snapshots are a part of UFS2 and that they work
just fine with or without soft updates.

I was wondering if the problems I've seen are limited strictly to
gjournal-based UFS2 systems.  I'm guessing that they are, based upon
the fact that the problems are dramatic enough to have shown up in
discussion if they were widespread.  But I also wondered if perhaps
the additional concurrency associated with multiple processors might
be a factor.

As it is, it may be prudent for someone intending to use dump with
snapshots to hold off on building filesystems with gjournal until this
is resolved.

Other than this problem, the gjournal/ufs integration has worked
flawlessly here.