Sun Microsystems Sun Fire V480, Руководство администратора

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Chapter 4 Network Interfaces and System Firmware 63
Stop-D Functionality
The Stop-D (Diags) key sequence is not supported on systems with USB keyboards.
However, the Stop-D functionality can be closely emulated by turning the system
control switch to the Diagnostics position. For more information, see “System
Control Switch” on page 18.
About Automatic System Recovery
The system provides for automatic system recovery (ASR) from the following types
of hardware component failures:
■
CPUs
■
Memory modules
■
PCI buses and cards
■
FC-AL subsystem
■
Ethernet interface
■
USB interface
■
Serial interface
Automatic system recovery functionality enables the system to resume operation
after experiencing certain non-fatal hardware faults or failures. When ASR is
enabled, the system’s firmware diagnostics automatically detect failed hardware
components, while an auto-configuring capability designed into the OpenBoot
firmware enables the system to unconfigure failed components and restore system
operation. As long as the system is capable of operating without the failed
component, the ASR features enable the system to reboot automatically, without
operator intervention.
During the power-on sequence, if a faulty component is detected, the component is
automatically unconfigured and, if the system remains capable of functioning
without it, the boot sequence continues. In a running system, certain types of failures
(such as a processor failure) can bring the system down. If this happens, the ASR
functionality enables the system to reboot immediately if it is possible for the system
to function without the failed component. This prevents a faulty hardware
component from keeping the entire system down or causing the system to crash
repeatedly.
To support such a degraded boot capability, the OpenBoot firmware uses the 1275
Client Interface (via the device tree) to “mark” a device as either
failed or disabled , by
creating an appropriate “status” property in the corresponding device tree node. By
convention, the Solaris operating environment will not activate a driver for any
subsystem so marked. Thus, as long as the failed component is electrically dormant
(that is, it will not cause random bus errors or signal noise, for example), the system
can be rebooted automatically and resume operation while a service call is made.