Installing CentOS On An External USB Drive
I decided to get a dedicated server for my project and passion of the moment (more on that later, maybe). As a result, I wanted to set up a CentOS installation so that I could work out all the bugs before uploading. Unfortunately, it turns out that getting CentOS working on a USB drive is not as easy as, say, Ubuntu or Slax, and it took some googling before I got it to work.
Installing CentOS To An External USB Drive
- When you boot CentOS and get to the initial screen, type “linux expert”. This will enable you to format/partition your external USB drive.
- When you reboot, reboot to the CentOS CD AGAIN and type “linux rescue”. This (should) mount your USB drive.[1]
- Navigate to the /boot directory of your USB drive and rebuild the initrd for USB support with:
mkinitrd --with-usb --preload=ehci-hcd --preload=usb-storage --preload=scsi_mod --preload=sd_mod ./usbinitrd-X.X.XX-X.XXXX_LLL X.X.XX-X.XXXX_LLL. The right X.X.XX-X.XXXX_LLL codes can be seen under /lib/modules, just choose the appropriate one.[2] - Change your grub configuration to point to your new USB initrd.
Voila! CentOS goodness on an external USB drive.
[1]If your drive isn’t automatically mounted (or the wrong one is mounted), do a
mkdir /mnt/usb; mount /dev/sda1 /mnt/usb, substituting the appropriate device for /dev/sda1.
[2]See this forum thread for more details
[3]Simon’s guide to USB booting is the canonical guide for RH
[...] ???Installing CentOS On An External USB Drive????????????????????! [...]
Hi there,
Just installed CentOS 4.8 on a 16Gb OCZ Rally and it just worked out of the box!
I didn’t have to rebuild the initrd at all… hope this info helps someone.
Hi from me too!
I just installed CentOS 5.5 onto a 32GB USB flash drive using step 1. Had to use the “linux expert” since the generic installer didn’t show my usb flash drive.
Even though I told it to install the OS to the flash drive on sdb, it only wanted to put grub on sda so I opted out of installing the bootloader. Needless to say, it wouldn’t boot after the install.
Used step 2 to get to a shell. chrooted to the flash drive and used grub-install /dev/sdb1 to get grub on it.
Still wouldn’t boot because there was no grub.conf. Used step 2 again and created a simple grub.conf.
I’m now running CentOS off a flash drive for demos of our work. When demo is over, remove the stick and reboot.
Thanks!
Shayne
[...] From the link you posted to: brool.com/index.php/installing-centos-on-an-external-usb-drive [...]