sats

Installing Red Hat Linux ES v3 on an USB External Hard Drive
--------------------------------------------------------------------------

This documents my experiences in installing Red Hat Linux ES v3 on an external USB hard drive, so that I could run Linux by booting from the hard drive without affecting the internal Windows XP disk at all. I tried this on Dell Inspiron 6000 Notebook computer with Intel Pentium M processor.

Requirements

Before attempting this it is assumed that you understood the system requirements for installing Linux Enterprise Server v3.
The supported method requires the creation of a boot CD with the rest of the installation being carried out using ISO image CDs o! f Linux ES v3 software.
Make sure that the target machine can boot from CD/DVD and USB as well as the internal hard drive. I found it most convenient to set my Dell Inspiron 6000 boot order to
i) DVD
ii) USB
iii) Internal HDD

so that the USB takes precedence over the hard-drive and the DVD has highest priority for installat! ion (I can still over-ride this order by hitting F12 during a reboot).
In case if you have chose the boot order as
i) DVD
ii) Internal HDD
iii) USB,
Each time you what to boot Linux, you need hit F12 during boot and then have to select USB to boot Linux. This option can be used after successful completion of the Linux ES v3 installation on USB Hard Disk.

Installation

The key to installing onto the USB drive is to boot from the installation media and then type expert at the first prompt. This is undocumented, but allows the installation process to modify the external drive.

At the prompt for a Driver Disk, select NO, then continue by selecting the appropriate keyboard and installation media. Skip the Media Test, it takes a long while, although for peace of mind you might want to run it the first time you run through the installation procedure.

When you get to the disk partitioning process, select auto partitioning. Make sure you that the internal hard disk should not recognized. It only recognizes internal hard disk if it has any unformatted disk space available to do partitioning (This is my understanding!). However ignore the original hard disk at all times. By default installation will display /boot, / (root) and swap partitions. Modify them as suits to you. You will need to make a /boot partition, a / pa! rtition, and at least one /swap partition (swap partitions are 2 GB maximum, if you want more swap space than this you will need to create more partitions). If you want to share data with Windows you will need to make a vfat partition, although this can be an extended partition. Note that the /boot and /partitions must be primary partitions. Force them to be primary partitions. You will get a check box to force them to be primary partitions.! You need to verify this before proceeding further.


I ended up with these disk partitions:

/dev/sda
/dev/sda1 /boot ext3 4096 MB
/dev/sda2 / ext3 <AVAILABLE SPACE>
/dev/sda3 /data vfat 71680 MB
/dev/sda4 Extended
/dev/sda5 swap 2048 MB

Note:

Vfat partition is not mandatory. If created it can be used to store your multi media stuff and other stuff from Windows XP or other windows based Operating Systems.
Extended partition created automatically by Installation if there are more than 3 partitions created.
/(root) partition takes all the space available automatically after all partitions are created unless specified by you.

After this point installer will take care of actual partitioning and formatting of the USB Hard Disk, when the installer asks where to install the boot-loader, select "advanced boot loader options" as you need to load grub into the Master Boot Record (MBR) of the external disk. This allows you to change the disk order. Make sure it you select the external hard disk MBR at this point. Now you get to configure network, etc., and then can choose which packages to install. Your selects for network or other options should not have any impact on successful installation and booting from USB Hard Disk.

Post Installation

Do not reboot your system from hard disk or USB drive yet!!
When this is all finished, again boot from CD the install media and type linux rescue at prompt. Don't start the network, skip the probe for installation, and it will go to the optional shell. Issue the following commands:

mount /dev/sda2 /mnt/source
(This chooses your / partition, use the appropriate partition label.)

mount /dev/sda1 /mnt/source/boot
(Use the partition for your /boot partition.)

chroot /mnt/source

mkinitrd --preload ehci-hcd --preload usb-storage --preload scsi_mod
--preload sd_mod /boot/initrd.img 2.4.21-37.EL
(This is a single command, execute! it after typing continuously with only single space gaps)

where initrd.img is the new boot ram-disk image you are creating, and 2.4.21-37.EL is the kernel version.

Nano is the editor. Use the editor to change! the ram-disk image for kernel in the config file to the ones you have just created.

nano /boot/grub/grub.conf

In this file change following entries:

For Kernel entry change root=LABEL=/ to root=/dev/sda2 (this should be your /(root) partition).

For initrd entry change image file <eg.initrd-2.4.21-37.EL.img> to initrd.img (this is the n! ewly created ram-disk image in earlier steps).

Save the File.

Reboot system and remove the CD from the drive. And select boot options to boot to USB drive.

Note that each time you do a kernel upgrade you will need to repeat the above steps for kernel, but it will be easier as you can access the /boot partition from an earlier kernel without the need of a rescue disk.
Make sure you run the firstboot initializations after rebooting from the disk for the first time, and then perform the updates.

THIS SHOULD SEE YOU THROUGH THE INSTALLATION…GOOD LUCK…

anaea

Thanks for posting one of the best known documents to install RHEL 3.0 using USB external hard drive.


Just wanted to add my experience in here. (Dont know if my experience is DELL specific). I tried it a couple of times (incidentally on the same hardware Dell Insp 6000) and it didnt recognize the external hard drive during the partition stage.

To fix this problem, enter your bios and change the USB Emulation settings from the default (emulate) to NO. Dont worry if your USB hard drive doesnt appear in boot display. Just boot from cdrom and proceed (following the instructions). And VIOLA you'll see a sda drive in automatic partitioning.

After installation is done, please change the bios settings back to Emulate.

Cheers

jkoshi

sats,

Thanks very much for this detailed procedure.
I went through this to install RH Enterprise Linux 4 on a usb drive. At the
end, when I rebooted from the usb drive, I get the error message "Missing
operating system"....I went back and checked everything once again, but
with the same result.
Any reason why I'm running into this?

regards,
John

clow2821

Hi,
Has any one successfully installed Redhat Enterprise 4 on USB external Drive? I tried following the instruction from sats but could not get it to work.
Any help is greatly appreciated.

Thanks

Chen

JatMan

I could install RHEL AS 4 Update 4 with these instructions.

lroque

Hi JatMan, I did it too, but when rebooting it seems to look for USB HDD patitions on the internal HDD instead of USB HDD.
Can you help me?

JatMan

Iroque,
Make sure the BIOS is set to boot from USB HDD in the boot-priority list. You may have a CD-ROM as the first and then, USB HDD as the second.

velmots83

First of all, Thanks --sats-- ,

this is as one of the best documents for installing RHEL 3 & 4 on usb disks.
for people who has problems with RHEL 4, did you make USB disk the first boot device?
i dont know, but i just followed the instructions and everything is fine.