New install fails to boot.

chris_andrew · Posted: Thu Aug 03, 2006 6:48 am Post subject: New install fails to boot.

Hi, all.

I have just done my first Gentoo install, for a while. I have rebooted after the install, and get the following:

Sedrik · Posted: Thu Aug 03, 2006 7:08 am Post subject:

Can be a missconfigured grub.conf
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sblaineyuk · n00b Joined: 27 Oct 2005 Posts: 34

Do you have a whoe disk slice? either /dev/sda3 or /dev/hda3?

chris_andrew · Posted: Thu Aug 03, 2006 10:17 am Post subject:

Hi,

I am almost sure it was /dev/hda3. Because I can't boot, I am not sure how to check this, or grub.conf. Can I use the Gentoo cd as a rescue disk, to look?

Thanks,

Chris.

Ferris · Posted: Thu Aug 03, 2006 11:05 am Post subject:

Yes. If you have a liveCD you can boot, you should be able to do see how your disk is formatted by checking it with fdisk. Here is an example of a good disk from a live U60 (but not from the boot CD; this system is running normally):

Ferris · Posted: Thu Aug 03, 2006 11:19 am Post subject:

By the way, you are talking about grub and grub.conf. Since this is sparc, I hopt that is a typo, and that you really mean silo and silo.conf. And after you install silo, don't forget to follow the instructions about running "silo -f" or "silo -f -C /boot/silo.conf" or whatever, depending on how you set up your system (documentation and the output from the silo install will tell you what to do based on your specific setup.) If you forget this step, your disk will not be bootable: Running silo writes a boot block onto the disk, and this is a little kernel loader loader (it loads the program which loads the kernel, and the "silo -f" sets it up so that the preloader can find the actual loader). There is much more information than anyone could want at http://www.sparc-boot.org/ --- a site dedicated to explaining how silo works.

.

chris_andrew · Posted: Thu Aug 03, 2006 3:06 pm Post subject:

Hi, I emerged SILO, IAW the SParc Quick Install, but don't remember doing the -f thing. Hmmm....

Ferris · Posted: Thu Aug 03, 2006 5:14 pm Post subject:

As indicated previously, after you install silo, the disk on which you installed it is pretty much guaranteed not to be bootable unless you run silo, too (there should be a block of warning messages at the end of the silo install alerting you to this). Depending on how your particular system is set up, just running silo with no arguments might be enough. (I.e., if your silo.conf is /etc/silo.conf). In any event, silo must have installed into the actual /boot directory you are going to be using (separate partition or not), and then 'silo -f -C <absolute-path-to-silo.conf>' should always be safe, I believe. Please check 'man silo' for details, or look at the silo web site I mentioned a couple posts up.

Regards,

chris_andrew · Posted: Thu Aug 03, 2006 6:27 pm Post subject:

Ferris,

How do I achieve this, if I can't boot into Gentoo? I need to know how to use the LiveCD as a rescue disk.

Cheers,

Chris.

Ferris · Posted: Thu Aug 03, 2006 7:50 pm Post subject:

Just boot it like you were doing an install. If you have /boot as a separate partition, you should be able to mount it and run silo (assuming you have set up a correct silo.conf). Or, If you have a good root partition on your disk, mount it on /mnt/gentoo (or some such), follow the instructions in the installation guide for doing a chroot into /mnt/gentoo, mount /boot (if necessary), make sure you have a good silo.conf, and run silo.

The keys are: (1) you have the installation CD; (2) You do have a good installation on your disk(s). All that you really need beyond that is a good /boot directory (separate partition or not) and a good silo.conf on the same disk. One way or the other, you have to get your /boot directory on the disk to be what you are calling /boot on the system you are running. If it's a separate partition and has your silo.conf in it, you can just mount it. Otherwise, you have to go through the chroot step.

It sounds confusing, but it really isn't. I don't know how your disk is partitioned; that is why I am going through these alternatives. So, think of it like this:
1. Boot CD;
2. Mount your root partition (on the disk) on /mnt/gentoo, just as if you were doing an install;
3. Follow the instructions to chroot into it.

4. Now, if /boot is NOT a separate partition, it is mounted, too. Make sure your silo.conf file is correct, and run silo as described earlier.

5. If /boot IS a separate partition, mount it onto /boot (from within the chroot). Make sure silo.conf is correct, etc.

In either case, if your kernel is good, silo.conf is good, and your disk is formatted correctly, you should be ready to go.

Sorry for the confusion,
Regards,
Ferris