Question

dmesg and /var/log/messages loglevel configuration

Asked by: doolyo

I dont' know if I am getting it right, but I have understood that the dmesg kernel messages are stored in /var/log/messages by the help of syslog, and that syslog was adding a timestamp before each message, is that right?
In that case, why are not all messages of dmesg stored in /var/log/messages and would there be a loglevel we could change so that it woudl log all messages from dmesg?

This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.

Subscribe now for full access to Experts Exchange and get

Instant Access to this Solution

  • Plus...
  • 30 Day FREE access, no risk, no obligation
  • Collaborate with the world's top tech experts
  • Unlimited access to our exclusive solution database
  • Never be left without tech help again

Subscribe Now

Asked On
2007-10-27 at 01:31:21ID22921796
Tags

dmesg

,

log

Topics

Kernel And Operating System Specific Programming

,

Linux Administration

,

Linux

Participating Experts
3
Points
350
Comments
9

Trusted by hundreds of thousands everyday for fast, accurate and reliable tech support.

  • "The time we save is the biggest benefit of Experts Exchange to Warner Bros. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange." Mike Kapnisakis, Warner Bros.
  • "Our team likes having a resource that is more secure than just using Google and most experts using this service really know their stuff. It's nice to look here first versus using Google." Dayna Sellner, Lockheed Martin
  • "Anytime that I've been stumped with a problem, 9 out of 10 times Experts Exchange has either the accepted solution or an open discussion of the potential solution to the problem." Kenny Red, eBay Inc.

See what Experts Exchange can do for you.

Got a question?

We've got the answer.

Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.

Screenshot of Experts Exchange Knowledgebase

Need individual assistance?

Our experts are ready to help.

If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.

Screenshot of Experts Exchange Knowledgebase

Want to learn from the best?

Read articles from industry experts.

Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.

Screenshot of an Article

Working on a long term project?

Store your work and research.

Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.

Screenshot of Experts Exchange Knowledgebase

Access the answers to your technology questions today.

Subscribe Now

30-day free trial. Register in 60 seconds.

What Makes Experts Exchange Unique?

Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.

Trusted by the world's most respected brands.

image of each brand's logo

Faithfully serving IT professionals since 1996.

Experts Exchange Logo

Try it out and discover for yourself.

Subscribe Now

30-day free trial. Register in 60 seconds.

Related Solutions

  1. log message in my "dmesg" file
    Hi could someone tell me what this message means in my "dmesg" log file?: MASQ: failed tcp/udp checksum from 202.331.xxx.xxx! (thats not the ip) thanks, eureeka
  2. NIC not recognized in boot (no le0 or hme0 in dmesg)
    I've recently installed Solaris 8 Intel Edition and had to install without networking because the installer would fail, reporting that my IP had changed during a configuration, causing a core dump. So I installed without it, but now my PCI NIC is not recognized at boot time ...
  3. can't display last  information.and can't get dmesg mes…
    one ultra10.use # last wtmp begins Tue Jan 2 21:16 # but you can see more /var/adm/wtmpx's information. what cause this??and how to do.. one ultra5.use # dmesg Jun 9 16:02 Can't read kernel memory # but can see /var/adm/messages that file is ok... but why OS give m...
  4. Solaris 8 dmesg question
    The company tht I work for builds solid state disk drives. A customer that we have sent me an E-Mail with the following line of text from a 'dmesg' request. I don't know how to translate the information, could some one help. The text that I received is as follows: "A...
  5. Transcend IDE Flash DMESG errors - unusable / Ubuntu
    DMESG: [ 4.764617] ata2.00: ATA-0: TRANSCEND 064M, 1.1, max PIO2 [ 4.764621] ata2.00: 125184 sectors, multi 1: LBA [ 4.764872] ata2.00: failed to set xfermode (err_mask=0x1) [ 4.764877] ata2: failed to recover some devices, retrying in 5 secs [ 9.928292] ata2.00: failed to s...

Free Tech Articles

  1. WARNING: 5 Reasons why you should NEVER fix a computer for free.
    It is in our nature to love the puzzle. We are obsessed. The lot of us. We love puzzles. We love the challenge. We thrive on finding the answer. We hate disarray. It bothers us deep in our soul. W...
  2. SCCM OSD Basic troubleshooting
    SCCM 2007 OSD is a fantastic way to deploy operating systems, however, like most things SCCM issues can sometimes be difficult to resolve due to the sheer volume of logs to sift through and the dispe...
  3. Migrate Small Business Server 2003 to Exchange 2010 and Windows 2008 R2
    This guide is intended to provide step by step instructions on how to migrate from Small Business Server 2003 to Windows 2008 R2 with Exchange 2010. For this migration to work you will need the fo...
  4. Create a Win7 Gadget
    This article shows you how to create a simple "Gadget" -- a sort of mini-application supported by Windows 7 and Vista. Gadgets can be dropped anywhere on the desktop to provide instant information, ...
  5. Outlook continually prompting for username and password
    There have been a lot of questions recently regarding Outlook prompting for a username and password whilst using Exchange 2007. There are a few reasons why this would happen and I will try to cover t...
  6. Backup Exchange 2010 Information Store using Windows Backup
    There seems to be quite a lot of confusion around the ability to backup Exchange 2010 using the built in Windows Backup feature. This stems from the omission of this feature prior to Exchange 2007 s...

Cloud Class Webinars

  1. Avoiding Bugs in Microsoft Access
    Alison Balter takes and in-depth look at avoiding bugs in Access. In this webinar you will learn about using the immediate window to debug your applications, invoking the debugger, using breakpoints to troubleshoot, stepping through code, setting the next statement to execute, ...
  2. Top 10 Best New Features in Visio 2010
    Scott Helmers gives live demonstrations of the top 10 new features in Visio 2010. This webinar will teach you how to create compelling diagrams by adding shapes to the page with a single click, linking the shapes in a diagram to data in Excel (or SQL Server, or SharePoint), ...
  3. IT Consultant Business Secrets Revealed
    Michael Munger, Experts Exchange tech pro and IT consultant, pulls back the curtain on his very successful businesses and answers question on every IT consultant and business owner should know about. He shares secrets on what he did to solve the 5 most common problems in IT, ...
  4. Disaster Recovery and Business Continuity
    Quest CTO, Mike Billon, gives an overview of the steps involved in building a dunamic disaster recovery plan. Through case studies and an examination of software/hardware tooles for monitoring and testing, you'll gain a better understandin of where you are, where you want ...
  5. Organize Your Visio Diagrams with Containers and Lists
    Scott Helmers uses cross functional flowcharts, wireframe diagrams, data graphic legends and seating charts to teach you: how to ustilize all three new structured diagram components in Visio 2010, the best practices for organizeing shapes in previous version of Visio, how to organize ...
  6. How to Us Objects, Properties, Events and Methods in Microsoft Access
    Alison Dalter gives an in-depbth look at objects, properties, events and methods in Microsoft Access. In this webinar you will learn about using the object browser, referring to objects, working with properties and methods, working with object variables, understanding the ...

Join the Community

Give a Little. Get a Lot.

Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.

Join the Community

Answers

 

by: Jozk0Posted on 2007-10-27 at 03:31:12ID: 20161028

they are stored under:

/var/log/boot.msg

this is on opensuse.

 

by: doolyoPosted on 2007-10-27 at 04:04:29ID: 20161068

I have very few information in this /var/log/boot.log file, much less than in the dmesg output.

 

by: ibu1Posted on 2007-10-27 at 04:31:50ID: 20161124

its in
/var/log/dmesg

 

by: doolyoPosted on 2007-10-27 at 04:38:42ID: 20161145

The output of dmesg seems to contain only the boot up messages. I had a lot of "TCP: Treason uncloaked!" messages when I typed 'dmesg'. I have deleted them with 'dmesg -c', and yet I would like to know where they have been stored. I thought it was in /var/log/messages, but yet they are not there nor in any suggested file above. Isn't this related to a loglevel configuration?

 

by: svsPosted on 2007-10-27 at 05:02:23ID: 20161183

syslog 'routes' all messages it receives to multiple logfiles and/or console.  You need to examine /etc/syslog.conf.  Manual pages (syslog and syslog.conf) should help you diagnose the problem (if there is one).

 

by: Jozk0Posted on 2007-10-27 at 05:03:10ID: 20161186

They are not stored on the disk, it's the kernel _buffer log_. These occur before any syslog service is started and reside only in the buffer. If you want, you can store them manually:

  dmesg -c > /var/log/dmesg_log

or add this into one of your startup boot scripts to perform this automatically.

 

by: Jozk0Posted on 2007-10-27 at 05:05:35ID: 20161192

sorry my mistake actually the above happens automatically after boot.

 

by: Jozk0Posted on 2007-10-27 at 05:26:57ID: 20161231

if you want to write the current kernel buffer, you will need to configure syslog accordingly, this differs strongly between syslogd and syslog-ng:

syslog-ng
------------
you need to specify a filter:

filter f_kernel    { level(warn) and facility(kern) and not filter(f_iptables)
                      or level(err) and not facility(authpriv); };

destination log file:

destination custom_log { file("/var/log/kernel_log"); };

and finally set logging:

log { source(src); filter(f_kernel); destination(custom_log); };

in syslogd
--------------
kern.*      /var/log/kernel_log

here are some links:

http://www.softpanorama.org/Logs/Syslog/syslog_configuration_examples.shtml
http://linux.cudeso.be/linuxdoc/syslog-ng.php

 

by: doolyoPosted on 2007-10-27 at 08:56:57ID: 20161843

Hello, Jozk0.
I am using syslogd. The following line in /etc/syslog.conf is probably what I need:
kern.*      /var/log/kernel_log
This seems to log almost everything, so I must wait that the event I am looking for comes out again and see if it is there. But as it seems to log all kernel messages, and that dmesg shows all kernel messages, I think that this is the solution to my problem!
Thanks a lot,
Daniel

20120131-EE-VQP-002

3 Ways to Join

30-Day Free Trial

The Experts

98% positive feedback on 31,087 answers since March 2000. angeliii is a Microsoft Most Valuable Professional for his work with MS SQL Server & Develoment.

He has also proven his knowledge of Visual Basic Programming, PHP Scripting and Oracle Databases.

The Experts

97% positive feedback on 10,752 answers since July 2000. lrmoore has more than 18 years experience in the networking industry.

The six-time Mircosoft MVPs specialties include firewalls, virtual private networking, and network management.

Testimonials

"...and excellent source for support... Kind of like having your very own IT dept." Electriciansnet

Testimonials

"I was apprehensive at signing up at first. However... it has already made my life as an IT administrator much easier." JaCrews

Testimonials

"WOW! You guys have great, active, and knowledgeable people on here." moore50

Business Clients

Business Clients

In the Press

"If you’ve got a question... Experts Exchange can supply an answer.”

In the Press

"...an invaluable aid for both IT professionals and those who require tech support."

In the Press

"where IT professionals provide quick answers on just about any topic"

Business Account Plans

Loading Advertisement...