debugging frequent kernel panics on 8.2-RELEASE

[Jeremy Chadwick]

On Wed, Aug 10, 2011 at 05:26:27PM +0100, Steven Hartland wrote:
> ----- Original Message ----- From: "Jeremy Chadwick"
> freebsd at jdc.parodius.com
> 
> >>>In combination with this, we use the following in /etc/rc.conf (the
> >>>dumpdev line is important, else savecore won't pick up anything):
> >>>
> >>>dumpdev="auto"
> >>
> >>I thought this was ment to be the default from back in the 6.x days but
> >>it didnt seem to work, so I added the gptid device from /etc/fstab
> >
> >/etc/defaults/rc.conf has dumpdev="NO", which affects two things: both
> >/etc/rc.d/dumpon (this script is a little tricky, you really have to
> >read it slowly/pay close attention to what's going on), and
> >/etc/rc.d/savecore.
> 
> Hmm, someone might want to correct the docs then:-
> http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug.html
> 
> "AUTO is the default as of FreeBSD 6.0"

It used to be "auto", and was changed to "no" in this commit back in
September 2009, and was reviewed by two separate people:

http://www.freebsd.org/cgi/cvsweb.cgi/src/etc/defaults/rc.conf#rev1.358.2.2

Prior to that, it was "auto", as confirmed here (circa June 2005):

http://www.freebsd.org/cgi/cvsweb.cgi/src/etc/defaults/rc.conf#rev1.250

So basically the documentation is both correct and incorrect.  For
anyone running FreeBSD later than September 2009 (I would need to spend
some time figuring out what releases that was), dumpdev will not be
enabled by default.  Prior to that (which includes 6.x), it will be.

The documentation needs to be updated to reflect reality (specifically
the commit that was done in September 2009).  I'll file a PR for this,
but won't have the PR number until later today.

-- 
| 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 |