Process enters unkillable state and somewhat wedges zfs

[Daniel Andersen]

I'm certainly not an expert on this, but from my understanding, I think Andriy Gapon had some thoughts on this
particular problem and potential solutions:

http://lists.freebsd.org/pipermail/freebsd-fs/2014-November/020482.html

At least, I think these problems are related.

>From my end, my 'solution' was to stop using nullfs mounts in conjunction with zfs.  :(  Fortunately, our jail servers
don't use zfs, yet.  Since I reorganized our data NFS server to stop using nullfs, it's been very stable.  ( aside from
one crash when it's raid 1 boot drive somehow went offline.. but I'm fairly sure that had nothing whatsoever to do with
the ZFS problems. )

Dan

On 12/17/2014 01:53 AM, Michael Ranner wrote:
> Hello there!
> 
> I have the same problem on FreeBSD 9.3-RELEASE-p6.
> 
> mount_nullfs of ZFS dataset in jail environment.
> 
> php-fpm process get stuck (100% CPU, unkillable) and the specific ZFS dataset is unaccessible. Further processes
> accessing the same dataset are hanging in state zfs.
> 
> Other datasets on the same pool are still accessible.
> 
> The stack trace looks very similar to Daniels.
> 
> Is there any progress on this?
> 
> I have many very similar environments (jail, ZFS, nullfs mounts), so I am interested in some solution or workaround.
> 
> -- 
> Mit freundlichen Grüßen
> 
> Ing. Michael Ranner
> 
> GSM:  +43 676 4155044
> Mail: michael at ranner.eu
> WWW:  http://www.azedo.at/
>