How to restore all of /boot/?

[Bryan Miller]

Okay. Since you have several disks, the system could be booting from
the other one. What I usually do is have two boot partitions in a dual
HDD raid setup--one boot part each. I'll use this as an example. You
seem to know what you're doing, so I'm going to assume you can apply
my example to your setup.

I have sda and sdb as drives in the raid setup.

The first part is always boot:

/dev/sda1 & /dev/sdb1

After I could get the system to boot, I would login as root and then run grub:

# grub
>device (hd0) /devv/sda
>root (hd0,0)
>setup (hd0)
>device (hd0) /dev/sdb
>root (hd0,0)
>setup (hd0)

This would always solve any grub related boot problem for my setup.

Apply steps to your setup accordingly. :)

If your setup only has a boot part on one drive, my guess would be
that the system is not booting from that drive?

If you do have to resort to rsync'ing stuff, my advice would be to
boot into single mode by putting "single" at the end of the kernel
line in grub (press e upon grub menu, then e again on the kernel
line). From there, bring up the network via service or init.d, and
then sync files. Nothing should be running in single mode that would
prevent this from completing successfully.

Hope this helps.

-Bryan


On Fri, Aug 22, 2008 at 2:10 PM, Landreth, Kevin
<klandreth at theplanet.com> wrote:
>> I also tried 'root (hd0,0)' and 'setup (hd0,0)'
>
> I should be
> # Grub
>> root (hd0,0)
>> setup (hd0)
>
> Not (hd0,0)
>
>
>
> -----Original Message-----
> From: linux-poweredge-bounces at dell.com
> [mailto:linux-poweredge-bounces at dell.com] On Behalf Of Zembower, Kevin
> Sent: Friday, August 22, 2008 3:28 PM
> To: linux-poweredge at dell.com
> Subject: RE: How to restore all of /boot/?
>
> Bryan and Kevin, thanks so much for your suggestions. Bryan, I ended up
> following your directions, but it still didn't help me and now I'm at a
> standstill. As far as I can tell, /boot/ and /boot/grub/ are fully
> populated. /boot/contains files System.map, config, initrd, sysvers and
> vmlinuz, all for 2.6.18-92.1.1.el5. /boot/grub/device.map looks
> identical to another of my systems that uses GRUB and LVM. I tried both
> '/sbin/grub-install /dev/sda1' and '/sbin/grub-install /dev/sda' after
> booting the CentOS 5 rescue mode and 'chroot /mnt/sysimage'. Neither one
> reported an error, but neither one fixed the problem. I also tried 'root
> (hd0,0)' and 'setup (hd0,0)' from the grub prompt. Again, reported
> 'success' but didn't fix the problem.
>
> I'm at a loss for what to do next. Are there any diagnostics or logs in
> grub? Any way to tell what's going on just before it goes to the grub>
> prompt? The word 'GRUB...' flashes by, but that's all I can read before
> it clears the screen and goes to the grub> prompt.
>
> If I can't get this working, I think I can still recover the system by
> installing CentOS 5 normally, then rsyncing with the files on the other
> server. I was avoiding this because I don't know what files and
> directories changed, and I don't think I'll be successful just rsyncing
> the whole /td/ directory, because of open and in-use files. However, I
> can't think of an alternative at this time. Any suggestions?
>
> Thanks, again, for all your help and advice. Have a good weekend.
>
> -Kevin
>