Re: Dmesg is not showing whole boot list

[Kyle Moffett]

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.

Cheers,
Kyle Moffett
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