How do I debug the shutdown process ?

[Erwin Smout]

I have an init.d process that absolutely requires a clean shutdown. (It's not as "absolute" as the term suggests, but that's past the point. I WANT the process to shutdown cleeanly because recovering takes more time than just waiting for the clean shutdown.)

However, after a couple of days it always happens that seemingly, the stop() call to the init.d script simply does not happen. I've added echo>> to the script and the output simply doesn't appear in the file system if and when the failure occurs.

K5 at runlevels 0 1 6 and S95 at the others (all pretty standard and the numbers ensure the stop() for this process must be one of the first to be fired. The service is java so the os process is a JVM.

How can I inspect what is actually going on in the shutdown process in order to diagnose the problem ?

[Snowhog]

Have you examined dmesg?

[Erwin Smout]

I think I have, and found nothing telling, but :

- would that be /var/log/dmesg ? If not, then how do I obtain dmesg output ?
- might have been looking on the wrong day (I guess I need to look on the first day following failure, specifically)
- how do I prevent the subsequent boot from overwriting any useful output produced during the previous shutdown ?
- the interweb documents dmesg as logging BOOT output. My problem is a SHUTDOWN problem. Does shutdown output even appear in dmesg ?

(Oh, yes, and sudo service stop manually never failed so far.)

[Snowhog]

Open a console and just type: dmesg

[Erwin Smout]

Can't find anything in dmesg output. What should I be looking for ?

[Erwin Smout]

I found rumours of problems when you shutdown immediately from the desktop. Since I've developed the habit of first logging out and only then shut down, the problem no longer seems to appear. So even if I still don't know how to debug the shutdown process, a bypass for my actual problem has been found.