Sun SPARC[R] Enterprise Mx000 Servers (OPL) How to send a break to a domain and how to disable a break signal

Asset ID:	1-71-1020179.1
Update Date:	2011-03-07
Keywords:

Solution Type Technical Instruction Sure

Solution 1020179.1 : Sun SPARC[R] Enterprise Mx000 Servers (OPL) How to send a break to a domain and how to disable a break signal

Applies to:

Sun SPARC Enterprise M9000-32 Server - Version: Not Applicable to Not Applicable - Release: N/A to N/A
Sun SPARC Enterprise M9000-64 Server - Version: Not Applicable to Not Applicable   [Release: N/A to N/A]
Sun SPARC Enterprise M3000 Server - Version: Not Applicable and later    [Release: N/A and later]
Sun SPARC Enterprise M4000 Server - Version: Not Applicable to Not Applicable   [Release: N/A to N/A]
Sun SPARC Enterprise M5000 Server - Version: Not Applicable to Not Applicable   [Release: N/A to N/A]
All Platforms

Goal

What is a "Break signal"?
Break means to forcibly interrupt the domain and restore the initial state. For example to recover from a hung domain. The signal used for this purpose is called a break signal. When a break signal is sent from a domain console, XSCF receives the signal and stops the domain at an ok prompt.

Note: When working with a hung domain consult <Document 1020078.1> Sun SPARC(R) Enterprise Mx000 Servers: How to deal with a hung or unresponsive domain.

Solution

How to enable and disable the domain responding to the break signal:

There are two switches involved in controlling the behavior of the sendbreak command:

The physical keyswitch on the Operator Panel has 2 positions:

Locked: When the keyswitch is in locked position the domains ability to process a break signal depends on the Secure mode setting.
Service Setting the keyswitch to the service position will allow a domain to process the break signal ( no matter the Secure Mode setting ) and will suppress the domains ability to auto-boot .
The software "Secure Mode" switch, set by using the XSCF setdomainmode command, is either on or off. Use the showdomainmode command to view this switches setting.

off: Will allow processing of a break while keyswitch is in the Locked position.
on: Will not allow the sendbreak command to work on this domain while the keyswitch position is Locked.

Normally a system should be run with the Operator Panel keyswitch in Locked position and the software "Secure Mode" switch set to "on".

Examples:

XSCF>showdomainmode -d 0 
Host-ID :0f010f10 
Diagnostic Level    :min 
Secure Mode         :off 
Autoboot :on 
CPU Mode :auto 

XSCF>setdomainmode -d 0 -m secure=on 
Diagnostic Level    :max     -> - 
Secure Mode :off -> on 
Autoboot :on -> - 
CPU Mode :auto -> - 
The specified modes will be changed. 
Continue? [y|n]:y 
configured. 
Diagnostic Level :max 
Secure Mode :on (host watchdog: available  Break-signal:non-receive) 
Autoboot :on (autoboot:on) 
CPU Mode :auto

The behavior is described in detail in the
Sun SPARC Enterprise M3000/M4000/M5000/M8000/M9000 Servers XSCF User's Guide

Note: When the Operator Panel Switch is turned to "Service" the break signal will always be executed regardless of the setting of "Secure mode". To view the setting of the Operator Panel Switch use "showhardconf".

XSCF> showhardconf
SPARC Enterprise M4000 ;
    + Serial:BCF070500E; Operator_Panel_Switch:Service;
[more output omitted]

How to send a break signal to a domain

Documented:

A break signal can be send to a domain using the "sendbreak" command.

XSCF>sendbreak -d 0 
Send break signal to DomainID 0?[y|n] :y

Not documented:

On a console connection (with the "console" command) apply the following key combination "ctrl" and "\" resulting in ascii value 0x1c (decimal = 28). This will also send a break signal .

Internal Comments
Source code of the undocumented "ctrl -\"
Search for: "break signal from telnet"

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