dmesg output

[amit kumar_5]

Hi All,
i have one query regarding the out
put of dmesg. can any body tell me from where exactly this command gets the information and how it is different from syslog information.

amit

[RAC_1]

There is buffer that keeps meesages that you see in dmesg. This is circular buffer and when new information is received, old one is flushed out. What you see in dmesg is also logged in syslog.log

/var/adm/msgbuf is the file that holds dmesg buffer information. This can be refreshed as when you want.

[Adisuria Wangsadinata_1]

Hi,

The different is on dmesg, the message on buffer cache (system buffer). So when the system restart, the message will be cleared. And if there's a new message, the first message will be gone (as follow FIFO rules).

On syslog, the message will be stay on the file (syslog.log & OLDsyslog.log). When the system rebooted, the system will save the syslog.log into OLDsyslog.log and will generate the new one.

For detail informations, check the man page :

# man dmesg
# man syslog

Hope this information can help you.

Cheers,
AW

[Arunvijai_4]

Hello Amit,

Here is a link to a good article, "dmesg explained"

http://linuxgazette.net/issue59/nazario.html

-Arun

[Muthukumar_5]

Message logging is based on /etc/syslog.conf. See that few messages will go to /dev/console and few settings will go to syslog.log. That is where getting differed.

Configure /etc/syslog.conf.

-Muthu