Date: Tue, 14 Mar 2006 13:34:24 -0500
From: Gene Heskett <gene.heskett@verizon.net>
Subject: Re: Dmesg is not showing whole boot list
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On Tuesday 14 March 2006 12:28, Kyle Moffett wrote:
>On Mar 14, 2006, at 12:16:23, Gene Heskett wrote:
>> On Tuesday 14 March 2006 10:05, Phillip Susi wrote:
>>> Or look in your /var/log/kern.log file instead of asking dmesg.
>>> dmesg just dumps the kernel ring buffer which is of finite size.
>>> The entire contents should be logged to /var/log/kern.log.
>>
>> You've got to have /var checked and mounted to be able to do that
>> log write, if the buffer overflows before that, then the head end
>> of the dmesg dump to the /var/log/dmesg file is lost forever.
>>
>> There is a line that can be changed, in xconfig or by hand, to
>> control the memory allocated for this ring buffer.
>>
>> Finally found it in the xconfig display, left panel line=kernel
>> hacking, right panel its under kernel debugging and shows only if
>> thats checked, double click on the line that says : kernel log
>> buffer size and enter a one digit increment from whats there now,
>> maybe 2, I have mine set for 16.  Your default may be as low as 14,
>> why I have NDI because 16k sure as heck isn't enough if something
>> gets chatty.
>
>To continue this point; on my desktop I have root/var/tmp/vicepa-on-
>LVM-on-RAID5, boot-on-RAID1, and swap-on-RAID1, so I would easily
>overflow the default SMP dmesg buffer size in messages well before
>syslogd/bootlogd got started.  I finally ended up having to increment
>the default by 3 in order to have the boot messages still available
>after booting.  It would be nice if we could quiet down some of the
>more excessively verbose kernel messages, there's a lot of mostly-
>irrelevant spew that chews up log buffer space.

I think thats somewhat true but then when you need that info for 
figureing out what didn't work, its priceless.  The only thing I'd 
stick a hot potato in is ACPI, its turned off in the config and still 
supplies about 5k of its mewling on boot.  But my /proc/interrupts says 
its not working, which is what counts so I can keep good time with 
ntpd.

>Cheers,
>Kyle Moffett

-- 
Cheers, Gene
People having trouble with vz bouncing email to me should add the word
'online' between the 'verizon', and the dot which bypasses vz's
stupid bounce rules.  I do use spamassassin too. :-)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
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