[CentOS] ext4?

Sat Aug 7 21:43:07 UTC 2010
Keith Roberts <keith at karsites.net>

On Sat, 7 Aug 2010, James Bensley wrote:

> To: CentOS mailing list <centos at centos.org>
> From: James Bensley <jwbensley at gmail.com>
> Subject: Re: [CentOS] ext4?
> 
> On 7 August 2010 19:59, Akemi Yagi <amyagi at gmail.com> wrote:
>> They are all installed. Are you using RAID by any chance? Your
>> grub.conf indicates that is from the second drive.
>
> /dev/sda1 / (ext3)
> /dev/sda2 /storage (the ext4 in question, hardware RAID5 3.4TB)
> /dev/sdb1 /boot (ext3)
>
> It seems like grub and/or yum have gone wrong somewhere over the years
> and perhaps downloaded new kernels but not installed them?
>
> What would be a solution I should seek to achieve, compile them
> myself? Or is there a way I can tell my CentOS box "these are here,
> look you fool, use them!"?

Well that's sort of what I do.

If you have space to create a separate boot partition for 
GRUB, about 20MB should be plenty. You can create it as an 
ext3 logical partition, inside an extended partition. That 
should solve the GRUB Centos issue.

You then need to reinstall GRUB to that separate boot 
partition, otherwise GRUB will still be looking to boot from 
the MBR of the first drive - if that's where it is now.

You can install GRUB to separate boot partition by:

Create the separate boot partition, and label it 
something like GrubBoot, using e2label /dev/sd?? GrubBoot.

create the mountpoint; /mnt/GrubBoot

==================================================================
** AutoLinuxInstaller Fedora Installation

I have created a seperate Grub boot logical partition, in 
the extended partition, called GrubBoot /dev/sda13. This enables 
me to do fresh Linux installations into /dev/sda1 and /dev/sda2, 
without destroying the GrubBoot partition.

Here's a URL to my partition layout:

http://i34.tinypic.com/r9nccz.jpg

from grub-install man page:

`--root-directory=DIR'
       Install GRUB images under the directory DIR instead of
       the root directory. This option is useful when you want
       to install GRUB into a separate partition or a removable
       disk. Here is an example in which you have a separate "boot"
       partition which is mounted on `/boot' (I use /mnt/GrubBoot):

The installation of grub to the seperate partition was done 
by:

First mount the GrubBoot partition with:

mount -v -t ext3 -L GrubBoot /mnt/GrubBoot

then

grub-install --root-directory=/mnt/GrubBoot hd0

This was done with F12 as the active OS. Centos 5.5 and F12 
will boot now from the GrubBoot partition.

I noticed that re-installing GRUB from Centos 5.5 did not 
allow Fedora 12 to boot. But for some strange reason, when I 
re-installed GRUB from Fedora 12, this also allowed Centos 
5.5 root partition to boot.

Here is what my /mnt/GrubBoot/boot/grub/grub.conf file looks 
like. Note I've added some dummy entries at the end to 
distinguish where GRUB is booting from:

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You do not have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /, eg.
#          root (hd0,0)
#          kernel /boot/vmlinuz-version ro root=/dev/sda1
#          initrd /boot/initrd-version.img
#boot=/dev/sda

#   GRUB     Linux
#   hd0,0    /dev/sda1   1st hard drive,1st partition
#   hd0,1    /dev/sda2   1st hard drive,2nd partition
#   hd0,2    /dev/sda3   1st hard drive,3rd partition

#   GRUB     Linux
#   hd1,0    /dev/sdb1   2nd hard drive,1st partition
#   hd1,1    /dev/sdb2   2nd hard drive,2nd partition
#   hd1,2    /dev/sdb3   2nd hard drive,3rd partition

#   GRUB     Linux
#   hd2,0    /dev/sdc1   3rd hard drive,1st partition
#   hd2,1    /dev/sdc2   3rd hard drive,2nd partition
#   hd2,2    /dev/sdc3   3rd hard drive,3rd partition

default=0
timeout=5
splashimage=(hd0,12)/boot/grub/splash.xpm.gz
hiddenmenu

title Initial CentOS 5.5 DVD kernel (vmlinuz-2.6.18-194.el5)
      root (hd0,0)
      kernel /boot/vmlinuz-2.6.18-194.el5 ro root=LABEL=Centos-5-root noapm apm=off ide=nodma
      initrd /boot/initrd-2.6.18-194.el5.img

title CentOS 5.5 system (vmlinuz-2.6.18-194.8.1.el5)
      root (hd0,0)
      kernel /boot/vmlinuz-2.6.18-194.8.1.el5 ro root=LABEL=Centos-5-root noapm apm=off ide=nodma
      initrd /boot/initrd-2.6.18-194.8.1.el5.img

title Fedora 12 system (vmlinuz-2.6.32.12-115.fc12.i686.PAE)
          root (hd0,1)
          kernel /boot/vmlinuz-2.6.32.12-115.fc12.i686.PAE ro root=LABEL=Fedora-12-root noapm apm=off ide=nodma nomodeset
          initrd /boot/initramfs-2.6.32.12-115.fc12.i686.PAE.img

title Fedora 12 system (2.6.31.9-174.fc12.i686.PAE)
          root (hd0,1)
          kernel /boot/vmlinuz-2.6.31.9-174.fc12.i686.PAE ro root=LABEL=Fedora-12-root noapm apm=off ide=nodma nomodeset
          initrd /boot/initramfs-2.6.31.9-174.fc12.i686.PAE.img

title Fedora 12 system (2.6.31.5-127.fc12.i686.PAE)
          root (hd0,1)
          kernel /boot/vmlinuz-2.6.31.5-127.fc12.i686.PAE ro root=LABEL=Fedora-12-root noapm apm=off ide=nodma nomodeset
          initrd /boot/initramfs-2.6.31.5-127.fc12.i686.PAE.img

title ...
          root (hd0,0)
          kernel /boot/vmlinuz-2.6.27.5-117.fc10.i686 ro root=LABEL=Fedora-10-root noapm apm=off ide=nodma
          initrd /boot/initrd-2.6.27.5-117.fc10.i686.img

title ...
          root (hd0,0)
          kernel /boot/vmlinuz-2.6.27.5-117.fc10.i686 ro root=LABEL=Fedora-10-root noapm apm=off ide=nodma
          initrd /boot/initrd-2.6.27.5-117.fc10.i686.img

title *** (Booting from GrubBoot logical partition /dev/sda13) ***
          root (hd0,0)
          kernel /boot/vmlinuz-2.6.27.5-117.fc10.i686 ro root=LABEL=Fedora-10-root noapm apm=off ide=nodma
          initrd /boot/initrd-2.6.27.5-117.fc10.i686.img

Sorry for all the noise. Just want to help the guy.

Kind Regards,

Keith Roberts

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