gmirror panic on RELENG_8

[Steve Price]

On Tue, Jan 11, 2011 at 7:00 AM, Miroslav Lachman <000.fbsd at quip.cz> wrote:
>
> There must be some odd problem in your case. I am running 8.2-RC1 with
> gmirror on production machine without any panic. The system was upgraded
> from 7.2.

I have the exact same hardware setup running in production
with 8.0.  This only happens when there are 3 drives (only have
3 hot swap bays so can't try more) in the box.  I've /dev/zero'd
all 3 drives before doing the install to make sure the contents of
the drives wasn't an issue.

If I have only drive, no problem.  2 drives, no problem.  The mere
presence of the 3rd drive on the bus and it panics.  With 2 drives
I can add the 3rd drive after boot like this and it works fine.

# camcontrol rescan 0:2:0
# sed -i.bak -e's,#/dev/da2s1d,/dev/da2s1d,g' /etc/fstab
# mount /b

The really troubling part is that I can't get a coredump. da0s1b
is an 8GB swap partition.

# grep dump /etc/rc.conf
dumpdev="/dev/da0s1b"
dumpdir="/var/crash"
# df -k | grep var
/dev/da0s1e     81122126    262   7472094     0%    /var
# sysctl hw.realmem
hw.realmem: 4227690496
# ls -ld /var/crash
drwxr-x---  2 root  wheel  512 Dec 23 15:00 /var/crash

Unless I'm missing something var has nearly twice the amount
of space to hold the entire contents of physical memory but on
panic it says:

Cannot dump. Decive not defined or unavailable.

/dev/zero'ing the whole drive is way overkill and takes forever
but even when I just zero out the last sector on each disk (which
is all that glabel should be caring about) it still panics when the
3rd disk is present.  Doesn't matter the order of the disks either.
Pick any 2 disks and it works. Use 3 in any order and it panics.

Do you see anything wrong with the way I'm trying to get a coredump?
If I could get that, I could get a better idea of where/how this is
happening.

Thanks.

-steve