From owner-freebsd-questions@FreeBSD.ORG Fri Dec 17 10:43:56 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id AC54916A4CE for ; Fri, 17 Dec 2004 10:43:56 +0000 (GMT) Received: from salmon.maths.tcd.ie (salmon.maths.tcd.ie [134.226.81.11]) by mx1.FreeBSD.org (Postfix) with SMTP id C7E9743D58 for ; Fri, 17 Dec 2004 10:43:55 +0000 (GMT) (envelope-from iedowse@maths.tcd.ie) Received: from walton.maths.tcd.ie by salmon.maths.tcd.ie with SMTP id ; 17 Dec 2004 10:43:54 +0000 (GMT) To: David Erickson In-Reply-To: Your message of "Mon, 13 Dec 2004 07:31:23 EST." <18716.153.2.247.31.1102941083.squirrel@www.mddsg.com> Date: Fri, 17 Dec 2004 10:43:53 +0000 From: Ian Dowse Message-ID: <200412171043.ab22303@salmon.maths.tcd.ie> cc: freebsd-questions@freebsd.org Subject: Re: Dmesg truncated X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 17 Dec 2004 10:43:56 -0000 In message <18716.153.2.247.31.1102941083.squirrel@www.mddsg.com>, David Ericks on writes: >I've been having this problem for quite a whlie but it's never bothered me >too much until I had some free time on my hand to look into it. Is there >any kernel parameter that could be truncating my dmesg buffer. Dmesg only >seems to have 1 line ever buffered which kinda sucks. I do have a custom >kernel built as thin as possible so im thinking that one of the options I >may have left out thinking I didn't need it or something along those >lines. The message buffer is used to store kernel log messages including console output as well as "normal" kernel messages; run `dmesg -a' to get the full message buffer contents. Typically these other log messages fill up the buffer so the kernel messages get overwritten. The logging of console output can be useful at boot time, but is often less important later since it is often just syslog messages that are already logged elsewhere. You can arrange for only boot-time console output to be recorded in the message buffer by adding the following line to the end of /etc/rc.local, creating that file if necessary (you could also use /etc/sysctl.conf, but rc.local is better because it happens a bit later): sysctl kern.log_console_output=0 Finally, you can increase the message buffer size by recompiling your kernel with a custom MSGBUF_SIZE setting. Ian