On my Ubuntu Server 14.04 I have large mdadm RAID6 array, and tiny boot HDD. I want to get rid of that boot HDD, and boot system from USB flash drive.

Although I know it is possible to install Ubuntu on a USB flash drive - I don't want to do it in order to limit writes to USB drive (that's literally asking for reliability troubles on a server).

Is there any guidelines or tutorials or suggestions on how to only move my initial steps (GRUB, initrd image e.t.c) of Ubuntu boot to USB stick, and then have / mounted on this RAID array?

Just to clarify - I don't want to move my whole system partition to USB drive, I only want to move the bare minimum there to limit writes on USB stick.


Moving the boot files to the USB disk wouldn't be too difficult - Moving / would be a large project; Instead, I suggest you consider reinstalling Ubuntu.

If you're willing to reinstall Ubuntu (you don't have to format your array during the reinstall), we can accomplish this without too much difficulty:

  • If you plan on not formatting the array, I suggest that you make a subdirectory on it, and move all the array's files into it. Since the array will be the new "/", any existing files will be found there, instead of the array's normal mountpoint.
  • Make sure the USB drive is attached before booting the installer
  • When configuring partitions:
    • format the USB drive using a Linux filesystem (like ext4), and set its mountpoint to "/boot"
    • Set the mountpoint of your array to "/" (If you want to keep the data on the array, make sure it's not makred to be formatted here.)
  • When configuring the bootloader, make sure that GRUB is set to be installed on the USB drive's device. (If the USB drive is already "sda", this should be the default.)

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.