:I've got a new panic.
:
:How can I be sure to get a crash dump ? This machine actually panicked
:once again before but for some reason didn't dump the core.
:
:It is sitting at the kernel debugger screen for the moment.
:
:--
:Francois Tigeot
It has to be setup before-hand. If it isn't there isn't much you can
do from the debugger. If it is setup before hand you can type 'panic'
from the debugger prompt & hit return twice (usually) and it will dump
before rebooting.
Generally speaking you set up to get a crash dump like this:
* Have enough swap space to cover main memory. i.e. if you 4g of
ram, you need 4g of swap.
* Set dumpdev to point to the swap device in /etc/rc.conf. Example:
'dumpdev=/dev/ad6s1b'. Takes effect when you reboot, you can
manually set the dumpdev on the running system by also running
'dumpon /dev/ad6s1b').
* Add 'kern.sync_on_panic=0' to your /etc/sysctl.conf to tell the
system not to try to flush the buffer crash when it crashes. This
improves its chances of being able to get to the dump code.
You can set the kernel up to automatically reboot on a panic (and
generate a crash dump if it has been setup to do one) by compiling
the kernel with:
options DDB
options DDB_TRACE
options DDB_UNATTENDED
-Matt
Matthew Dillon
<[EMAIL PROTECTED]>
