6.1 Chapter Objectives

• Minimize accidental system shutdowns

• Ensure continuity of OpenVMS cluster operations when individual members are shut down

• Achieve data integrity by ensuring that application-specific shutdown procedures are performed

• Explore the shutdown process in detail

• Use DCL procedures to automate common system-shutdown methods

6.2 Introduction

The following are typical situations that require a system shutdown:

• After a software installation or upgrade

• After changing nondynamic system parameters

• Before a power shutdown

• Before performing special booting procedures (e.g., system-disk backup)

There are two basic shutdown techniques:

1. Orderly shutdown

2. Emergency shutdown

An orderly shutdown removes installed images and dismounts all disks. These steps ensure that any critical operations in progress are allowed to complete before the system is actually halted. This reduces the risk of datafile and disk corruption. An emergency shutdown halts the system in a more abrupt manner. It is still better than simply turning the system off, but because cached data can be lost, you should use emergency procedures only when orderly shutdown procedures fail or if you need to force a system crash dump (discussed later in this chapter).

6.3 Orderly Shutdown Procedures

Before you actually activate SHUTDOWN, you may want to perform the following steps:

• Disable future logins

• Check for system activity

• Send a shutdown-notification message