System Administration Guide: Basic Administration

When to Shut Down a System

The following table lists system administration tasks and the type of shutdown method that is required to initiate the task.

Table 8–1 Shutting Down a System


Reason for System Shutdown	Appropriate Run Level	For More Information
To turn off system power due to anticipated power outage.	Run level 0, where it is safe to turn off power	Chapter 10, Shutting Down a System (Tasks)
To change kernel parameters in the `/etc/system` file.	Run level 6 (reboot the system)	Chapter 10, Shutting Down a System (Tasks)
To perform file system maintenance, such as backing up or restoring system data.	Run level S (single-user level)	Chapter 10, Shutting Down a System (Tasks)
To repair a system configuration file such as `/etc/system`.	See When to Boot a System	N/A
To add or remove hardware from the system.	Reconfiguration boot (also to turn off power when adding or removing hardware)	Adding a Peripheral Device to a System in System Administration Guide: Devices and File Systems
To repair an important system file that is causing system boot failure.	See When to Boot a System	N/A
To boot the kernel debugger (`kmdb`) to track down a system problem.	Run level 0, if possible	Chapter 10, Shutting Down a System (Tasks)
To recover from a hung system and force a crash dump.	See When to Boot a System	N/A
Reboot the system by using the kernel debugger (`kmdb`), if the debugger can't be loaded at runtime.	Run level 6 (reboot the system)	SPARC: How to Boot the System With the Kernel Debugger (`kmdb`) ,x86: How to Boot a System With the Kernel Debugger in the GRUB Boot Environment (`kmdb`)

For examples of shutting down a server or a stand-alone system, see Chapter 10, Shutting Down a System (Tasks).