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Question
I'm setting up a large software RAID array using MDADM, and don't want to waste a drive bay on a system disk. Unfortunately, the server I'm working with has trouble booting from a USB drive, so I'm attempting a workaround.

I want to create a LiveCD with Knoppix or some other suitable distribution, then use the USB drive as a mountable storage device to keep all my admin scripts etc on. I plan on running several services including:

Samba SSH SFTP Subversion (SVNServe)

I'm used to running a headless Fedora server, and that would be ideal, but I'll take what I can get. Can anyone suggest a good approach for this problem? Specifically - an appropriate distribution to use, how to configure the LiveCD, and how to get it to automatically mount and run certain scripts on the USB drive?

Answer 

Use grml, a bootable live system (Live-CD) based on Debian. Grml includes a collection of GNU/Linux software especially for system administrators and users of texttools. Grml provides automatic hardware detection. You can use Grml (for example) as a rescue system, for analyzing systems/networks or as a working environment. It is not necessary to install anything to a harddisk; you don't even need a harddisk to run it. Due to on-the-fly decompression Grml includes about 2.1 GB of software and documentation on the CD. 

Grml provides more than 2500 software packages. Excluding library stuff, more than 1700 packages remain. We don't ship KDE and OpenOffice, but more than 800 packages which for example Knoppix does not provide. You'll get sysadmin's favourite tools, security- and network-related software, data recovery- and forensic-tools, many editors, shells, and of course many texttools. Choose between different flavours (grml, grml-medium and grml-small) and a x86 and a amd64 version depending on your needs.

Grml provides several scripts and utils which make life easier. The default interactive shell is Zsh and is configured with a very powerful setup, including a nifty completion mechanism. grml-x is a wrapper for configuring and using the X window system. grml2usb is a tool for installing grml ISO(s) on a usb device for booting. grml-crypt is a program that provides an easy wrapper arround cryptsetup, mkfs, losetup and mount. grml-live is a build framework based on FAI (Fully Automatic Installation) for generating a grml and Debian based Linux Live system (CD/ISO). grml-tips provides useful tips and tricks for daily life on the command line. grml-vpn is a program to establish encrypted communication channels in a network, and so on...

(Debian based Linux Live-CD, check out grml.org):

• provides support for SW-RAID (mdadm) and LVM out of the box
• boot with 'grml ssh=passw0rd' -> a ssh server will be automatically started for remote access using the specified 'passw0rd' for user 'grml'
• if a device with label GRMLCFG is present (e.g. your USB drive) it will be automatically mounted and for automating tasks you can use a simple script named 'grml.sh' on it (which will be automatically executed if it's present)
• the tool grml-terminalserver provides easy setup of booting via network/PXE (if booting via CD/USB/... isn't an option for whatever reason)
• bootoption 'bootfrom=/dev/...' allows you to even mix booting from CD with USB :)