Re: FreeBSD 5.1-R kernel panic

On Wed, Jul 23, 2003 at 09:56:32AM -0600, Stephane Raimbault wrote:
> Hi Bosko,
> 
> Looking at netstat -m, the value I'd probably be interested in is the
> following:
> 
> 3% of cluster map consumed
> 
> knowing that the Maximum possible is 25600 I can deduce that ~768 are being
> used?  Is that correct.  I'm not much of a programmer, but I did recognize
> the printf(); statements from a C class I didn't do well in half a decade
> ago... as you can tell, I'm not much of a programmer :).  If it's not the 3%
> I should be paying attention too... then let me know :)

  Look at the "in pool" values for all the pcpu and GEN caches and add
  them up.  Do this for clusters (since there are fewer).  Compare to
  the "Maximum Possible" value.  With a machine that goes into
  spike-load periods, you may want to have the Maximum Possible stay
  about 4-6 times what you have as your average "in pool" value
  (remember to sum the "in pool" values for the pcpu and GEN caches).

  The 3% is not what you think it is.  It's the percentage of the
  allocated wired-down memory that is NOT in any of the caches but is
  allocated and circulating in the system.  If you have a high number of
  cached items but the percentage is relatively low for most of the
  time, it's a sign that you were probably in a heavy-usage scenario
  some time ago, but that your current usage is relatively low.
  
> As for using the option DDB in my kernel, I do have one question.  I do have
> remote console access that I use to go into single user mode on the box
> remotely.  I'm suspecting I could use the debugger mode over the
> comconsole... I just want to make sure there is some kind of reboot command
> from the debugger so that I can tell the box to reboot once I've captured
> the stack trace?  If so, I'll enable the DDB tonight and get you the info as
> soon as I can.

  Yes, you can do DDB over serial console.  Take a look at the handbook
  for more information on using DDB.  If you have the space in /var and
  enough swap, you may want to try getting a crashdump so that you can
  reboot and use GDB to debug.  Again, take a look at the handbook.

> thanks again,
> Stephane.

-- 
Bosko Milekic  *  bmilekic_at_technokratis.com  *  bmilekic_at_FreeBSD.org
TECHNOkRATIS Consulting Services  *  http://www.technokratis.com/