Ubuntu – Installing Ubuntu to a USB drive

bootexternal hard driveUbuntuusb

I'm having a rough time getting Ubuntu to run from a 250 GB USB hard drive.

I booted Ubuntu 9.10 from a CD and ran the regular "install" to the attached USB drive. I used the "advanced" option on the drive partition question to put the boot loader on /dev/sdb (the USB disk) but when I boot the machine it doesn't recognize there's a boot loader on the USB drive (it offers to boot from 2 other devices but not the USB disk).

I also tried booting from the Ubuntu CD and using usb-creator-gtk to set up the USB drive. Seems to me this is meant to work with flash drives. I got a bootable USB disk but it looked and worked like the CD, i.e. it gave me options of "live CD" operation, installing, memtest, etc. That's not the way I want to run the system.

Some help in installing Ubuntu, bootable into a "full" running system on my USB drive would be appreciated.

Best Answer

I assume from the size of the drive you are talking about, that you are either using a relatively expensive SSD or a spinning-disk based drive (rather than a "pen drive" or similar).

If using a spinning-disk based drive then you might find that the problem is due to the controller in the drive's enclosure not appearing to the BIOS as a bootable USB device until such time as the drive has fully spun up. Depending on how long the drive does take to spin up and how long the BIOS to do the rest of its POST. The POST will be shorter then when starting from a power-off state (usually no RAM test and so forth) for a warm boot so the drive has less time to be ready before it is scanned. This would explain you having more luck when power cycling the machine.

Some BIOSes have an option to pause for a few seconds before scanning for drives, to account for this possibility. If yours doesn't (it is less common now than it used to be) then you might have an option to force a full POST even on warm boot.