YEARS OF LINUX ADMINISTRATION have convinced me that you learn the most about a system by repairing it when it is broken. Nothing pushes you to the limits of
dd commands, or general shell know-how like a critical system that no longer boots. I have had my share of broken systems over the years—some my fault and some not—and in this chapter I describe some of the recovery techniques I find I use over and over again.
There are three main recovery tools I describe in this chapter. The first is the recovery boot mode that is included with a default Ubuntu Server install. This mode provides the most limited set of recovery tools, as it requires a system that can at least partially boot. The second is the ...