LPI Linux Certification in a Nutshell, 2nd Edition

Objective 2: System Recovery

Unfortunately, things don't always go well when working on a system . The most frequent system recovery happens automatically. Filesystems are fixed when booting, and while it takes some time, it's fully automatic most of the time. All other problems are infrequent.

One occasional problem is that one of the runlevel scripts cannot complete and causes the whole boot sequence to halt. This is easy to fix: just boot in single-user mode as described in Chapter 14, and edit the script. A harder problem is if the system initialization script or init somehow fails and foils the boot. Coping with this is described later in "init or the System Initialization Fails.

Filesystem Damage

Sometimes a filesystem is damaged in a way that the boot process does not want to fix automatically; in this case, it drops into a root password prompt with a display like the following (this is from Red Hat):

*** An error occurred during the file system check."
*** Dropping you to a shell; the system will reboot"
*** when you leave the shell."

Give root password for maintenance(or type Control-D for normal startup): password
(Repair filesystem) 1 #

After entering the password, you can fix the filesystem manually. Fixing a filesystem manually requires running fsck device. Answer y to all the questions. Answering anything but y to all the questions requires quite some knowledge of how your filesystem works. Very few have such knowledge, and so the questions are cunningly posed in such ...