linux-kernel - Re: Magic Sysrq key option ... What is the option to record the boot logs to my hard disk before i issue a reboot command ?

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Message-ID: <20181119234654.GD17374@thunk.org>
Date:   Mon, 19 Nov 2018 18:46:54 -0500
From:   "Theodore Y. Ts'o" <tytso@....edu>
To:     Randy Dunlap <rdunlap@...radead.org>
Cc:     AIAMUZZ <muzafsh.113@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: Magic Sysrq key option ... What is the option to record the boot
 logs to my hard disk before i issue a reboot command ?

On Mon, Nov 19, 2018 at 11:31:21AM -0800, Randy Dunlap wrote:
> 
> Yes, all of that.
> Having some kind of pstore on x86 would be wonderful.
> 
> kexec/kdump used to be an option also.  I haven't tried it lately.

Sure, but kexec/kdump won't work to debug a boot failure during early
boot.  You need to be able to get the root file system mounted at the
very least, and usually kexec/kdump doesn't get set up until the init
scripts are running.

Fortunately, usually only kernel developers need to debug early boot
failures, and most of us can usually use serial consoles (for those of
us who can't just cheat and use VM's.  :-)

       	     	  	    	       - Ted