About Configuring The System For For Troubleshooting; Hardware Watchdog Mechanism - Sun Microsystems Sun Fire V440 Diagnostics And Troubleshooting Manual

About Configuring the System for for
Troubleshooting
System failures are characterized by certain symptoms. Each symptom can be traced
to one or more problems or causes by using specific troubleshooting tools and
techniques. This section describes troubleshooting tools and techniques that you can
control through configuration variables.

Hardware Watchdog Mechanism

The hardware watchdog mechanism is a hardware timer that is continually reset as
long as the operating system is running. If the system hangs, the operating system is
no longer able to reset the timer. The timer then expires and causes an automatic
externally initiated reset (XIR), displaying debug information on the system console.
The hardware watchdog mechanism is enabled by default. If the hardware watchdog
mechanism is disabled, the Solaris operating environment must be configured before
the hardware watchdog mechanism can be reenabled.
The configuration variable error-reset-recovery allows you to control how the
hardware watchdog mechanism behaves when the timer expires. The following are
the error-reset-recovery settings:
boot (default) – Resets the timer and attempts to reboot the system
sync (recommended) – Attempts to automatically generate a core dump file
dump, reset the timer, and reboot the system
none (equivalent to issuing a manual XIR from the ALOM system controller) –
Drops the server to the ok prompt, enabling you to issue commands and debug
the system
For more information about the hardware watchdog mechanism and XIR, see
"Hardware Watchdog Mechanism and XIR" in the Sun Fire V440 Server
Administration Guide.
For information about troubleshooting system hangs: see:
"Responding to System Hang States" on page 123
"How to Troubleshoot a System That Is Hanging" on page 160
Chapter 6 Troubleshooting Options 109