dmesg : no output on 1 of 2 7-stable boxes

[Oliver Fromme]

Julian H. Stacey wrote:
 > Oliver Fromme wrote:
 > > The dmesg buffer is a circular buffer containing both
 > > kernel output and console output.  However, "dmesg"
 > > displays only the kernel output.  If there was lots of
 > > console output, it filled all of the dmesg buffer,
 > > so "dmesg" displays nothing (all of the kernel output
 > > was overwritten by console output).  "dmesg -a" will
 > > display everything, i.e. kernel + console output.
 > 
 > Some of that description could usefuly be added to `man dmesg` ?

I agree.

 > Might some commiter wnat to hack a few words in ?  Or do we neeed
 > a formal send-pr (that a commiter would rephrase likely anyway, so
 > best skip the send-pr ? ).

If you have the time, please submit a PR (docs category).
I'll take care of it.

You're a native English speaker.  I am not.  So chances
are that I won't rephrase it, except for technical
reasons.  And even if I did rephrase it, it's still a
good thing to have a PR, so the issue doesn't get lost
and forgotten.

 > > >    - I tried loader.conf        kern.msgbuf=64000
 > > 
 > > I think it must be a multiple of the pages size, i,e,
 > > 4K = 4096 on FreeBSD/i386.  I usually set it to 65536
 > > or 131072.
 > [...]
 > Puzzled on syntax to set size in loader.conf ?

Unfortunately it's a kernel constant, not a tunable.
The only way to change it is via "options MSGBUF_SIZE=..."
in your kernel config file, and rebuild the kernel.

Best regards
   Oliver

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  --  Sid on userfriendly.org by Illiad, 2007-06-20