Booting FC-6 via USB hard drive

sfjtraps · 02-21-2007, 04:49 PM

I have installed Fedora Core 6 a USB external hard drive, however it will not boot from that hard drive. I put the USB external hard drive first in the boot sequence. Also, during installation, I made a partition on the USB external hard drive and when prompted where to install the boot record, I checked the box indicating that it be installed on the USB external hard drive and not my computer hard drive.

If anyone has further ideas on how to get my Fedora Core 6 on my USB external hard drive to boot please let me know. Thanks

PTrenholme · 02-22-2007, 09:57 AM

Mine didn't work until I told my BIOS to enable "Legacy" USB support.

Also, I had a working Fedora on my hard drive, so I had to use a different logical volume name for the logical volume created on the USB drive. (By default, Fedora installs into logical volume VolGroup00, so, if you have two default installations, they will have the same logical volume name, and only one of them will be accessed.)

I also modified the GRUB configuration file on the HD so I could boot to either installation. Here's what (some of) my HD boot grub.conf menu entries look like:

Code:

title Fedora Core (2.6.19-1.2911.fc6)
        root (hd0,2)
        kernel /vmlinuz-2.6.19-1.2911.fc6 ro pci=assign-busses,nommconf enable_8254_timer root=/dev/VolGroup00/LogVol00 rhgb quiet
        initrd /initrd-2.6.19-1.2911.fc6.img
title Fedora Core (2.6.19-1.2911.fc6) USB connected
        root (hd1,2)
        kernel /vmlinuz-2.6.19-1.2911.fc6 ro pci=assign-busses,nommconf enable_8254_timer root=/dev/VolGroup00/LogVol00 rhgb quiet
        initrd /initrd-2.6.19-1.2911.fc6.img
title Fedora Core (2.6.19-1.2911.fc6) USB boot
        root (hd0,1)
        kernel /vmlinuz-2.6.19-1.2911.fc6 ro pci=assign-busses,nommconf enable_8254_timer root=/dev/Fedora/LogVol00 rhgb quiet
        initrd /initrd-2.6.19-1.2911.fc6.img

(The reason for the two HD boot entries is that (on my laptop) GRUB sets /dev/sda to (hd0) when the USB drive is connected, and sets /dev/hda to that same drive when the USP drive is disconnected.)

If you, too, have Fedora installed on the USB and the HD, here's the script I use to connect the USB drives whilst booted to the HD Fedora.

Code:

$ cat Scripts/MountUsb
#! /bin/bash
# Mount /dev/sda if it exists
if [ -b /dev/sda ]; then
    sudo /sbin/vgchange -a y Fedora
    sudo mount /usb
    sudo mount /usb/boot
    sudo mount /share
else
    echo Drive /dev/sda was not found.
fi

(The Fedora in both code snippets above is what I chose to call the logical volume on the USB drive. It is, of course, an arbitrary name, and you could use whatever you wished to use. As long as it did not duplicate an existing volume group name.)

<edit>
If you change the volume group name from the name used when the system was installed, you not only need to change the kernel and initrd lines in the grub.conf file to use the new volume group name, you also need to change the vgchange command in the nash script packed into the compressed initial RAM disk image file so it activates the new logical volume name instead of the old name. (The name of the volume to be activated is hard coded in the script.)
</edit>