[gentoo-amd64] Re: How to make watchdog start earlier during bootup?

[Duncan]

"P.V.Anthony" <pvantony@×××××××××××.sg> posted
49721DB1.6080200@×××××××××××.sg, excerpted below, on  Sun, 18 Jan 2009
02:04:33 +0800:

> On the motherboard the watchdog is de-activated. The watchdog timer is
> compiled into the kernel.
>
> During the bootup, when the server does a file system check, the server
> reboots without fulling booting up.
>
> The cause of the reboot is the watchdog in the kernel.
>
> Guessing that if the watchdog daemon was to start much earlier, it will
> prevent the kernel from rebooting. That will also allow more time to do
> a file system check. Currently to get the server to boot up, the setting
> of "0 0" is used so that it will not do a filesystem check.
>
> How to make the watchdog daemon start much earlier?

I'd check the documentation for your kernel watchdog driver.  My guess is 
that there's a kernel command-line option to disable it at boot, and 
something (a sysfs file or the like) you can prod later, to tell it to 
start, which you could then add to the watchdog daemon service script if 
there's not already provision for it.

Alternatively, you could of course compile the driver as a module and not 
have it load until later, but the kernel folks are pretty good about 
making it such that it can be compiled in if desired -- there's command-
line options and etc such that preventing early-activation or otherwise 
setting module options can be done from the command line instead, if it's 
built-in.  If that's /not/ the case here, and the documentation does not 
specifically /say/ that bit isn't working yet (which may be the case with 
an experimental driver or one still specifically under development), I'd 
consider not having a way to disable it thru boot and enable it later a 
bug, and I expect the kernel folks would as well.

FWIW, I too have the fsck service deactivated here, as you do, by setting 
the fsck order column in fstab to 0.  On reiserfs, which is what I run 
here for pretty much everything, it's not really needed anyway, since 
reiserfs  automatically does pretty much everything it could do in a 
normal fsck at mount in any case, and if it's beyond that, it's time for 
--rebuild-tree.  But I've not had to run that in /ages/, I think since 
the kernel got and activated by default data=ordered for reiserfs, and 
likely since I've been on Gentoo as well.  (IDR which came first, 
reiserfs data=ordered or my switch to Gentoo, but I sure do remember 
looking forward to each of them! =:^)  But, while that eliminates the 
(unnecessary for reiserfs) fsck time, because reiserfs can take a bit to 
replay the journal if the system crashed or the filesystems were 
otherwise not unmounted properly, you may end up with the same problem 
under those conditions.  

But, if you have no strong feelings against reiserfs (some do, but as I 
said I've been very happy with it since data=ordered became the default, 
YMMV), that might be another thing you could try.  At least you wouldn't 
have to feel so bad about missing the fscks then, and if you happen to be 
already running it, hey! =:^)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman