Failsafe on kernel panic

[Willem Jan Withagen]

On 17-1-2013 4:18, Ian Lepore wrote:
> On Wed, 2013-01-16 at 23:27 +0200, Sami Halabi wrote:
>> Thank you for your response, very helpful.
>> one question - how do i configure auto-reboot once kernel panic occurs?
>>
>> Sami
>>
> 
> From src/sys/conf/NOTES, this may be what you're looking for...
> 
> #
> # Don't enter the debugger for a panic. Intended for unattended operation
> # where you may want to enter the debugger from the console, but still want
> # the machine to recover from a panic.
> #
> options 	KDB_UNATTENDED
> 
> But I think it only has meaning if you have option KDB in effect,
> otherwise it should just reboot itself after a 15 second pause.

Well it is not the  magical fix-all solution.

Last night I had to drive to the colo (lucky for me a 5 min drive.)
because I could not get a system to reboot/recover from a crash.

Upon arrival the system was crashed and halted on the message:
	rebooting in 15 sec.

Which but those 15 secs are would have gone by for about 10-20 minutes.
fysically rebooting or resetting ended up in the same position:
	rebooting in 15 sec.
Without ever getting to actually rebooting.

So if I  (you) have servers 2 hours away, I usually try to work on
upgrading/rebooting during business hours. And remote hands can get me
out of trouble....

IPMI is another nice way of getting at the server in these cases. But
that requires a lot more infra and tinkering.

--WjW