Unplugging disk under ZFS yield panic

[Jeremy Chadwick]

On Wed, Jan 11, 2012 at 06:58:57PM -0500, Charles Sprickman wrote:
> 
> On Jan 11, 2012, at 4:43 PM, Fabian Keil wrote:
> 
> > Jeremy Chadwick <freebsd at jdc.parodius.com> wrote:
> > 
> >> On Wed, Jan 11, 2012 at 09:07:08PM +0100, Fabian Keil wrote:
> >>> Gergely CZUCZY <phoemix at harmless.hu> wrote:
> >>> 
> >>>> I'd like to ask, whether it is normal behaviour when we're unplugging a
> >>>> disk under a ZFS system then on the first write a kernel panic happened.
> >>> 
> >>> Sounds familiar. I currently have two PRs open for
> >>> reproducible kernel panics after a vdev gets lost:
> >>> http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/162010
> >>> http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/162036
> >>> 
> >>> Note that the pool layouts are different, though.
> >> 
> >> Is this problem truly ZFS-specific?  I'd been tracking this problem for
> >> years, and was told it was fixed:
> > 
> > I'm not saying that my problems are ZFS-specific.
> > The backtraces mainly contain geom functions and no ZFS code,
> > so ZFS might be the victim here.
> 
> Is there any relation between this issue and the "log_sysevent:
> type 19 is not implemented" problem that happens on device
> insertion/removal on 8.2?
> 
> http://lists.freebsd.org/pipermail/freebsd-fs/2011-June/011855.html
> 
> I still see that one on 8.2-STABLE from around 6/2011.  I initially
> thought it was triggered by device failure or removal (even with
> proper hotplug support), but I got hit by it last night when
> inserting a new drive in a chassis that supports ahci/sata hotplug.
> IIRC it's not a ZFS issue, ZFS just gets more spammy (well,
> extremely spammy to the point the system can't do much else) about
> reporting an issue with a device going away or being inserted.

This was fixed in RELENG_8 on 2011/06/14, r222343:

http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/cddl/compat/opensolaris/kern/opensolaris_sysevent.c#rev1.2.2.3

The code that would print that message is #if 0'd out now.  I can
confirm the message is gone on all our systems running recent RELENG_8.

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                   Mountain View, CA, US |
| Making life hard for others since 1977.               PGP 4BD6C0CB |