Sun Microsystems V490 manual What You Should Know About Accessing the ok Prompt, Graceful Halt

What You Should Know About Accessing the ok Prompt

It is important to understand that when you access the ok prompt from a functioning Sun Fire V490 system, you are suspending the Solaris OS software and placing the system under firmware control. Any processes that were running under the Solaris OS software are also suspended, and the state of such processes may not be recoverable.

The firmware-based tests and commands you run from the ok prompt have the potential to affect the state of the system. This means that it is not always possible to resume execution of the Solaris OS software from the point at which it was suspended. Although the go command will resume execution in most circumstances, in general, each time you drop the system down to the ok prompt, you should expect to have to reboot it to get back to the Solaris OS environment.

As a rule, before suspending the Solaris OS software, you should back up files, warn users of the impending shutdown, and halt the system in an orderly manner. However, it is not always possible to take such precautions, especially if the system is malfunctioning.

Ways of Reaching the ok Prompt

There are several ways to get to the ok prompt, depending on the state of the system and the means by which you are accessing the system console. In order of desirability, these are:

■Graceful halt

■Stop-A or Break key sequence

■Externally initiated reset (XIR)

■Manual system reset

A discussion of each method follows. For instructions, see “How to Get to the ok Prompt” on page 126.

Graceful Halt

The preferred method of reaching the ok prompt is to halt the operating system software by issuing an appropriate command (for example, the shutdown, init, halt, or uadmin command) as described in Solaris system administration documentation.

50 Sun Fire V490 Server Administration Guide • August 2004