System Administration Guide: Basic Administration

Chapter 7 Shutting Down and Booting a System (Overview)

This chapter provides guidelines for shutting down and booting a system. The Solaris software environment is designed to run continuously so that electronic mail and network resources are available to users. Occasionally, it is necessary to shut down or reboot a system because of a system configuration change, a scheduled maintenance event, or a power outage.

This is a list of the overview information in this chapter.

What's New in Shutting Down and Booting a System?

This section describes new features that are related to shutting down and booting a system in the Solaris 9 release.

PXE Network Boot

You can boot the Solaris x86 Platform Edition directly from a network without the Solaris boot diskette on x86 based systems that support the Preboot Execution Environment (PXE) network booting protocol. The PXE network boot is available only for devices that implement the Intel Preboot Execution Environment specification.

You can enable the PXE network boot on the client system by using the BIOS setup program in the system BIOS, the network adapter BIOS, or both. On some systems, you must also adjust the boot device priority list so that a network boot is attempted before a boot from other devices. See the manufacturer's documentation for each setup program, or watch for setup program entry instructions during boot.

Some PXE-capable network adapters have a feature that enables a PXE boot if you type a particular keystroke in response to a brief boot-time prompt. This feature is ideal when you use PXE for an install boot on a system that normally boots from the disk drive because you do not have to modify the PXE settings. If your adapter does not have this feature, disable PXE in the BIOS setup when the system reboots after installation, and the system will boot from the disk drive.

Some early versions of PXE firmware cannot boot the Solaris system. If you have one of these older versions, your system can read the PXE network bootstrap program from a boot server, but the bootstrap will not transmit packets. If this problem occurs, upgrade the PXE firmware on the adapter. Obtain firmware upgrade information from the adapter manufacturer's web site. For more information, see elxl(7D) andiprb(7D).

For information on booting x86 based systems with or without the boot diskette, see x86: How to Boot a System From the Network.

Where to Find Shutting Down and Booting Tasks

Use these references to find step-by-step instructions for shutting down and booting a system.

Shut Down and Boot Task	For More Information
Shut down a SPARC based system or an x86 based system	Chapter 9, Shutting Down a System (Tasks)
Boot a SPARC based system	Chapter 10, SPARC: Booting a System (Tasks)
Boot an x86 based system	Chapter 11, x86: Booting a System (Tasks)
Manage a SPARC based system with the power management software	power.conf(4), pmconfig(1M)

Shutting Down and Booting Terminology

This section describes the terminology that is used in shutting down and booting a system.

Run levels and init states – A run level is a letter or digit that represents a system state in which a particular set of system services are available. The system is always running in one of a set of well-defined run levels. Run levels are also referred to as init states because the init process is used to perform transitions between run levels. System administrators use the init command to initiate a run-level transition. This book refers to init states as run levels.

For more information about run levels, see Run Levels.
Boot types – A boot type describes how a system is booted. Different boot types include the following:
- Interactive boot – You are prompted to provide information about how the system is booted, such as the kernel and device path name.
- Reconfiguration boot – The system is reconfigured to support newly added hardware or new pseudo devices.
- Recovery boot – The system is hung or an invalid entry is prohibiting the system from booting successfully or from allowing users to log in.

Guidelines for Shutting Down a System

Keep the following in mind when you shut down a system:

Use the init and shutdown commands to shut down a system. Both commands perform a clean system shutdown, which means that all system processes and services are terminated normally.
Use the shutdown command to shut down a server, because logged-in users and systems that mount resources from the server are notified before the server is shut down. Additional notification of system shutdowns by electronic mail is also recommended so that users can prepare for system downtime.
You need superuser privileges to use the shutdown or init command to shut down a system.
Both shutdown and init commands take a run level as an argument. The three most common run levels are as follows:
- Run level 3 – Means that all system resources are available and users can log in. By default, booting a system brings it to run level 3, which is used for normal day-to-day operations. Also known as multiuser level with NFS resources shared.
- Run level 6 – Stops the operating system and reboots to the state that is defined by the initdefault entry in the /etc/inittab file.
- Run level 0 – Means that the operating system is shut down and it is safe to turn off power. You need to bring a system to run level 0 whenever you move a system, or add or remove hardware.
Run levels are fully described in Chapter 8, Run Levels and Boot Files (Tasks).

Guidelines for Booting a System

Keep the following in mind when you boot a system:

After a system is shut down, it is booted by using the boot command at the PROM level on a SPARC based system or by using the boot command at the Primary Boot Subsystem Menu on an x86 based system.
A system can be rebooted by turning the power off and then back on. This method is not a clean shutdown because system services and processes are terminated abruptly. However, turning a system's power off and back on is an alternative for emergency situations.
SPARC based systems and x86 based systems use different hardware components for booting. These differences are described in Chapter 12, The Boot Process (Reference).

Booting a System From the Network

You might need to boot a system from the network under the following situations:

When the system is first installed.
If the system won't boot from the local disk.
If the system is a diskless client.

In addition, there are two network configuration boot strategies available:

RARP (Reverse Address Resolution Protocol and ONC+ RPC Bootparams Protocol)
DHCP (Dynamic Host Configuration Protocol)

The default network boot strategy is set to RARP.

Use this table if you need information on booting a system over the network.

Network Boot Task	For More Information
Boot a SPARC system or a SPARC diskless client	Chapter 10, SPARC: Booting a System (Tasks)
Boot an x86 system or an x86 diskless client	Chapter 11, x86: Booting a System (Tasks)
Boot a DHCP client during installation	Solaris 9 9/04 Installation Guide
Configure a DHCP client with DHCP Manager	System Administration Guide: IP Services

When to Shut Down a System

The following table provides a list of system administration tasks and the type of shut down that is needed to initiate the task.

Table 7–1 Shutting Down a System


Reason for System Shut Down	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 9, Shutting Down a System (Tasks)
To change kernel parameters in the `/etc/system` file	Run level 6 (reboot the system)	Chapter 9, 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 9, 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)	“Managing Devices (Tasks)” in System Administration Guide: Devices and File Systems
To repair an important system file which is causing system boot failure	See When to Boot a System	N/A
To boot the kernel debugger (`kadb`) to track down a system problem	Run level 0, if possible	Chapter 9, Shutting Down a System (Tasks)
To recover from a hung system and you want to force a crash dump	See When to Boot a System	N/A

For examples of shutting down a server or a standalone system, see Chapter 9, Shutting Down a System (Tasks).

When to Boot a System

The following table provides a list of system administration tasks and the corresponding boot type that is used to complete the task.

Table 7–2 Booting a System


Reason for System Reboot	Appropriate Boot Type	Information for SPARC Procedure	Information for x86 Procedure
To turn off system power due to anticipated power outage	Turn system power back on	Chapter 9, Shutting Down a System (Tasks)	Chapter 9, Shutting Down a System (Tasks)
To change kernel parameters in the `/etc/system` file	Reboot the system to run level 3 (multiuser level with NFS resources shared)	SPARC: How to Boot a System to Run Level 3 (Multiuser Level)	x86: How to Boot a System to Run Level 3 (Multiuser Level)
To perform file system maintenance, such as performing a backup or restoring system data	Use Control-D from run level S to bring the system back to run level 3	SPARC: How to Boot a System to Run Level S (Single-User Level)	x86: How to Boot a System to Run Level S (Single-User Level)
To repair a system configuration file such as `/etc/system`	Interactive boot	SPARC: How to Boot a System Interactively	x86: How to Boot a System Interactively
To add or remove hardware from the system	Reconfiguration boot (also to turn on system power after adding or removing hardware)	“Adding a System Disk or a Secondary Disk (Task Map)” in System Administration Guide: Devices and File Systems	“Adding a System Disk or a Secondary Disk (Task Map)” in System Administration Guide: Devices and File Systems
To boot the kernel debugger (`kadb`) to track down a system problem	Booting `kabd`	SPARC: How to Boot the System With the Kernel Debugger (`kadb`)	x86: How to Boot a System With the Kernel Debugger (`kadb`)
To repair an important system file that is causing system boot failure	Recovery boot	SPARC: How to Boot a System for Recovery Purposes	x86: How to Boot a System for Recovery Purposes
To recover from a hung system and you want to force a crash dump	Recovery boot	See example on SPARC: How to Force a Crash Dump and Reboot the System	See example on x86: How to Force a Crash Dump and Reboot the System

For examples of booting a system, see Chapter 10, SPARC: Booting a System (Tasks) or Chapter 11, x86: Booting a System (Tasks).