ZFS snapshot Folder Disappearing

[Guido Falsi]

On Tue, Aug 28, 2012 at 07:35:46AM +0100, Matthew Seaman wrote:
> > I got hit by this a few times too. Ti me it looks like it's easier to
> > get this problem on more low spec machines(low spec regarding ZFS, so
> > anything under 3-4 GiB ram is on the low side, for example).
> 
> My machine has 8GB RAM which I wouldn't call low spec particularly.

No, Definitely not. But in my experience when I have upgraded machines
showing this problem it's frequency decreased a lot.

> 
> > Using nullfs across snapshots did trigger this easily. I did that to
> > have a nullfs mounted snapshot of the whole filesystem structure. I'm
> > using read only zfs clones for that now.
> 
> Interesting.  I do have certain ZFSes null-mounted into a jail.  I
> wonder if that's a common factor?

That could be a common trigger in my opinion, but it just exposes some
other problem. I know very little about ZFS internals so I have been
unable to dig any further.

-- 
Guido Falsi <mad at madpilot.net>