On Sat, 2005-01-29 at 21:30 -0500, Deron Meranda wrote:
> > Matthew Miller wrote:
> > >It's really not doing much. But if you want to see what's going on, edit
> > >your /etc/grub.conf and remove the keyword "quiet" from your kernel boot
> > >parameters.
>
> But there's still more to see! Here's how I do it...
>
> If you really want to see the little details (especially important if your boot
> sequence is hanging), then try this hackery (only works in FC3--or
> presumably later). Everything's as root (obviously).
>
> If necessary, you can also do most of this booted from the rescue CD.
> Just prefix pathnames with "/mnt/sysimage" as needed (you'll also have
> to use the "vi" editor as nothing else is available).
>
>
> ** To increase debugging levels in early "initrd" boot **
>
> What we are going to do is to edit the "initrd" file (normally located
> at /boot/initrd-2.6.10-1.741_FC3.img or similar). We will turn on
> even more debugging than is available by commenting out the
> "quiet" option of the kernel boot options. Since this file is not a
> simple text file, editing it involves many steps...
>
> cd /boot
> mkdir newinit
> cd newinit
> gunzip -c ../initrd-2.6.9-1.724_FC3.img | cpio -idmv
> # or whatever initrd version file you have
>
> At this point edit the "init" file, which is a nash script (this is NOT
> a normal shell script, so don't go adding lots bash-isms), changing:
>
> 1. Comment out the line "setquiet" (prefix with "#" character)
> 2. Change the "lvm vgscan" to "lvm vgscan -v"
>
> If you want more LVM debugging, also edit the etc/lvm/lvm.conf
> file and change
> verbose=1
> and
> level=3
> both inside the log() function (around line number 80). There are
> other LVM debugging options you can set if you want even more.
>
> Repackage up a new image. First rename the original one out of
> the way to save it so you can restore it later.
>
> find . | cpio --quiet -c -o >../newinitrd
> cd .. # You are now in /boot
> gzip -9 < newinitrd > initrd-2.6.9-1.724_FC3.img
>
> (If you're really paranoid be sure you have another bootable entry
> in your grub configuration---perhaps one that points to the same
> kernel but the original initrd file).
>
>
> *** To add debugging to hardware detection during boot ***
>
> You know that one line at the begging of the boot where it says
> "Initializing hardware...", and it goes through storage, audio, etc.
> Well, you can get more details, especially useful when you have
> a bad device or driver hanging...
>
> Edit /etc/rc.d/rc.sysinit (save a backup of the file first using
> cp -p /etc/rc.d/rc.sysinit /etc/rc.d/rc.sysinit.fc3
> In the function load_module(), add at the top, add an "echo" line
>
> load_module() {
> echo load_module($1)
> ...
>
> This is a bash script, so you can be more creative in how you add
> debugging...just be aware that you're still in single-user mode (or
> earlier).
>
> There are plenty of other places in that file that you may want to
> add some debugging output (by adding "echo" commands). Some
> of them might be anyplace a "modprobe" or "insmod" is run.
> If you have problems with loading keymap, then find the "loadkeys"
> command and add a -v option.
>
> Even if you have no problems, doing all this will help you really
> learn how Linux boots.
>
> Have fun.
> --
> Deron Meranda
>
Great Post, added to my Notes Folder.
