Chapter 11: After a System Crash

• Steps to take when a system crashes:
1. Enter into single user or safe mode:
• System cold start takes place when the system's is unable to automatically recover itself to a secure state. This is when an administrator gets involved.
• The systems will have two options:
1. Automatically boot up to a "single user mode"
2. Manually boot up to a "recovery console"
• The administrator must physically be at the console or have deployed external technology such as secured dial-in/dial-back modems attached to serial console ports or remote keyboard video mouse [KVM] switches attacked to graphic consoles.
2. Fix issues and recover files:
• Single user mode:
• Admin salvages file systems from damage that may have occurred as a result of the unclean, sudden shutdown of the system, and attempts to identify cause of the shutdown to prevent it from recurring.
3. Validate critical files and operations:
• If the shutdown suggests corruption then the admin must validate the contents of configuration files and ensure system files are consistent with their expected state.