SUSE Conversations


How to create an external USB bootable Linux hard drive (without dual-boot)



By: rjdunn

April 25, 2008 8:35 am

Reads:3894

Comments:15

Rating:2.3

The topic of a bootable external USB Linux hard drive (without dual-boot) is an area that is not well documented. A simple Google search shows many articles, blogs and forum posts written on this topic, all of them discuss setting up dual-boot strategies. While I did not specifically test a USB Thumb Drive and did not intend to address this device in this article, I see no reason why this would not work for Thumb Drives as well. This article was written with the goal of defining an alternative to the traditional dual boot concept and keeping each operating system isolated from each other.

While the dual-boot scenario works, this can cause undesirable issues when grub installs its files on the external drive. Should Grub install its files to the external drive, the drive must be connected before booting the computer or you will receive a Grub 17or 21 error. Based on the testing I have done in an effort to achieve the desired results, I did not want a dual-boot on either the laptops operating system (internal hard drive) or on the external USB drive.

This document applies to SLES 10 SP1, SLED 10 SP1, OpenSUSE 10.3; however based on my testing I feel that this will work with any Linux distribution. You will want to use laptop or desktop hardware in which the BIOS supports booting to a USB device.

Why would you want to do this?

Small foot print USB powered external drives are very obtainable and affordable. These drives come in various sizes with the most common and cost effective today being 250GB. This gives you the ability to:

  1. Test new OS versions
  2. Carry multiple working OS’s with you in the field
  3. Lab issues in the field
  4. Test patches
  5. Perform demonstrations

All of the above and more without risking the OS installed in your laptop or desktop. While this solution may not be right for everyone; this will provide you with more options.

There are several ways to achieve the results described herein; I will describe two of these methods and you can choose which method works better for your scenario.

Method 1:

  1. Insert the Linux OS Install CD/DVD
  2. Reboot the computer
  3. Enter the “Setup Menu”
  4. Disable the internal hard drive
  5. Save settings and exit
  6. The computer will reboot so you can see the Post Screen
  7. Push the appropriate key (F12 for Dell Laptops) to bring up the “One Time Boot Menu”
  8. Select boot from CD/DVD
  9. Install Linux OS (Follow your normal install procedure)
  10. The only device that should appear is the external USB drive
Note: Since the internal hard drive is disabled the Linux OS will have no choice, it will install all of the required components for the external USB drive to become a bootable device.

When the install has completed:

  1. Remove the Linux OS Install CD/DVD
  2. Reboot the computer
  3. Enter the “Setup Menu”
  4. Enable the internal hard drive
  5. Change the boot order to resemble
    1. USB Device
    2. Internal Hard drive
    3. CD/DVD
  6. Save settings and exit
  7. The computer will reboot so you can see the Post Screen (Let the system boot as normal)

The machine will boot into your newly installed Linux OS and will have no knowledge or connection to the OS that is installed on the computers internal hard drive.

Method 2:

  1. Insert the Linux OS Install CD/DVD
  2. Shout down the computer
  3. Remove the internal hard drive
  4. Start the computer
  5. The computer will boot so you can see the Post Screen
  6. Push the appropriate key (F12 for Dell Laptops) to bring up the “One Time Boot Menu”
  7. Select boot from CD/DVD
  8. Install Linux OS (Follow your normal install procedure)
  9. The only device that should appear is the external USB drive
Note: Since the internal hard drive was physically removed the Linux OS will have no choice, it will install all of the required components for the external USB drive to become a bootable device.

When the install has completed:

  1. Remove the Linux OS Install CD/DVD
  2. Shut down the computer
  3. Install internal hard drive
  4. Enter the “Setup Menu”
  5. Change the boot order to resemble
    1. USB Device
    2. Internal Hard drive
    3. CD/DVD
  6. Save settings and exit
  7. The computer will reboot so you can see the Post Screen (Let the system boot as normal)

The machine will boot into your newly installed Linux OS and will have no knowledge or connection to the OS that is installed on the computers internal hard drive.

Issue:

During one of my tests, after all of the above steps were completed Linux on the USB External Hard drive would not boot. The computer did not see the device as a bootable device therefore the machine booted to the OS installed on the internal hard drive.

Solution:

  1. Plug the external USB device into the USB port on the computer
  2. Place the Linux install CD/DVD in the CD/DVD drive on the computer
  3. The computer will boot so you can see the Post Screen
  4. Push the appropriate key (F12 for Dell Laptops) to bring up the “One Time Boot Menu”
  5. Select boot from CD/DVD
  6. The main install screen will give you the option to repair the Installed OS (during my tests this did not have any unwanted effects on the computers internal hard drive or the OS installed on it)
  7. Once the repair is completed remove the CD/DVD from the CD/DVD drive
  8. Reboot the computer

The computer should boot to the OS installed on the external USB drive without issue. However you need to understand the BIOS in your machine; I would suggest removing any USB devices except for the hard drive before booting the computer.

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How to create an external USB bootable Linux hard drive (without dual-boot), 2.3 out of 5 based on 3 ratings

Tags:
Categories: SUSE Linux Enterprise Desktop, Technical Solutions

Disclaimer: As with everything else at SUSE Conversations, this content is definitely not supported by SUSE (so don't even think of calling Support if you try something and it blows up).  It was contributed by a community member and is published "as is." It seems to have worked for at least one person, and might work for you. But please be sure to test, test, test before you do anything drastic with it.

15 Comments

  1. By:Anonymous

    Nice tutorial, but is there any way I would be able to boot off an external Hard Drive using a PC that doesn’t support USB boot?

    –robert

  2. By:Anonymous

    Thank You; That is most excellent prismatic prism! Yes most excellent indeed! The most excellent prismatic-prism spell. Thank for the info, now all joking aside, wouldn’t the booting Suse eventually ‘see’ and load the device drivers and partition map for the internally installed drive? I.e. after the install and after the 1st boot-up?

  3. By:Anonymous

    Robert,

    Based on my testing there has to be internal logic that understands how to boot from the external device. To be specific you can boot off an external harddrive if you are using SCSI or some other controller based technology that will allow for an external boot device. However to boot from an external USB the computers BIOS has to regonize and allow the machine to specifically boot from the USB port.

    Hope this helps!

    Rick.

  4. By:Anonymous

    I have been using these devices for almost a year now without any issues; I have not had an installation on an external USB drive try to modifiy anything on my internal harddrive. This solution looks very solid for now; I do test new versions of the OS as they become available to make sure this Cool Solutions remains relevant.

    Rick

  5. By:Anonymous

    Our school district uses Zen disconnected imaging to avoid network/bandwidth issues. There are several “Cool Solutions” we use to do so from USB flash and hard drives. You can download a bootable customized Zen 7.1 imaging OS from those pages to put on your USB device …Works Great!

    Problem: The 7.1 Zen imaging engine drivers no longer support all the newer hardware. The new Zenboot iso (10.1) has all the new drivers and seems to work fine with the new hardware, but…

    How can we make the 10.1 imaging engine bootable from a usb flash/hard drive? (Please make it as simple as possible. We have no Linux gurus here, just humble PC techs.)

    John

  6. By:Anonymous

    We had done this before reading your steps above. Now the internal hard drive will not boot. It comes up with some GRUB loading error. What do I need to change on that hard drive or is it toast?

    Jerry

  7. By:apatton

    Has any one ever gotten back to you on this? I’m looking for the same thing now, but only find tips on ZEN 7 usb imaging.
    Thanks

    Aaron

  8. By:rjdunn

    Hi Jerry,

    The easiest and cleanest way I have found in to start over from scratch with both your internal harddrive and the linux external usb harddrive. I know this is probably not what you wanted to hear; however in the long run it is your cleanest option.

    Rick

  9. By:punch_t

    Before attempting to install the OS to any USB device it is desirable to create a bootabole CD to enable you to boot your internal HDD. Having done this you can then reinstall the GRUB loader from your internal HDD. See the Grub manual on how to do this.

  10. By:shuja_khan

    Hi, I have never used Zen, but to make a USB flash bootable from ISO, please visit following

    http://unetbootin.sourceforge.net/

    Its open source tool.

    & download the windows version, it is standalone executable, you must have your bootable ISO available for USB flash, very easy. Scroll down the 1st option the last option is ZenWalk

    2nd option: path to your Zen iso file

    3rd option: before executing this executable, you must plug your USB flash to PC & check it in windows explorer that a drive letter is assigned to it such as D: or E: or may be F: etc.

    4th option: without doing any thing else, just click on OK, before making sure that the last bit is pointing to correct drive letter, click OK & few seconds later your usb is ready to rock & roll.

    Please update what is the result.

    Thanks

  11. By:korpx

    Good suggestion, it is a very nice tool. However the ZCM imaging installation has references to the physical cd and will stop booting in the NCURSES interface, and ask for the boot cd.

    I have not investigated if this can be tricked into working, but I am amazed how unflexible ZCM seem to be in this regard.

  12. By:rjdunn

    Hello All,

    I wrote this cool solutions as a standalone process; the intent was to create a bootable external usb harddrive without dual boot. I have not done the research or testing this process using ZEN; however if someone out there has real data on doing this using ZEN it would be great if it could be shared here too!

  13. By:_0_C-Zar_0_

    Gr8 Solution!
    Both easy 2 perform & pracitcable!
    If this works U have done a good job.
    I actually tried this without disabling the hard drive and my suggestion
    is DON´T! (It´ll screw Ur MBR on hda1)
    regards …

  14. By:Iomega1

    Valuable solution. It really works. I tried boot through external hard disk and it is a good news to all the users.

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