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?

• Where to Find Shutting Down and Booting Tasks

• Shutting Down and Booting Terminology

• Guidelines for Shutting Down a System

• Guidelines for Booting a System

• Booting a System From the Network

• When to Shut Down a System

• When to Boot a System

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.

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 11, Run Levels and Boot Files (Tasks).