6.0 random freezes

[Peter Jeremy]

On Mon, 2005-Dec-12 13:15:55 -0800, Atanas wrote:
>I have 3 machines running 6.0-RELEASE, and recently 2 of them started 
>freezing once a day or so. There are no error messages on the console or 
>in the system logs.
>
>The first one I put in production about a month ago and it was working 
>flawlessly until it got some load and now it started freezing almost 
>every day. The second one has exactly the same behavior - it was fine 
>when doing nothing (a couple of weeks), and started freezing when loaded.

Define "freezing":  Does it respond to pings?  Can you switch VTYs?
Do the num-lock/caps-lock LEDs respond?  Do some processes seem to
freeze before others?

I suggest you add the following to your kernel config:
 options         KDB                     # Enable kernel debugger support.
 options         DDB                     # Support DDB.

When it hangs, break into DDB (Ctrl-Alt-Esc on the console or BREAK on
a serial console).

As a start, run 'show lockedvnods' and 'ps'.  My guess is that you'll
see a lock that has a number of waiters - which is probably the
culprit.  Use 'panic' or 'call doadump' to get a crashdump and then
you can use kgdb to rummage around once you reboot - see
http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebg-gdb.html

>< makeoptions   DEBUG=-g             # Build kernel with gdb(1) debug symbols

I suggest you add this back in.  Without it, you can't debug any crash
dumps that you manage to get (and add "dumpdev" to your rc.conf).

>Now the only reasonable option for me (I mean for production and in 
>relatively short term) seems going downward to 5.4 and wait until 6.x 
>get more stable

Whilst I realise that you can't have production machines freezing on
schedule, your assistance in providing more information about your
problem will help make 6.x more stable.

-- 
Peter Jeremy