Sun Microsystems Fire 880, Руководство пользователя

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18 Sun Fire 880 Server Owner’s Guide • August 2001
Automatic System Recovery
The system provides for automatic system recovery (ASR) from the following types
of hardware component failures:
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CPUs
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Memory modules
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PCI buses and cards
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SCSI bus
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FC-AL subsystem
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Fast Ethernet interface
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Gigabit Ethernet interface
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USB interface
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Serial interfaces
The automatic system recovery feature allows the system to resume operation after
experiencing certain non-fatal hardware faults or failures. Automatic self-test
features enable the system to detect failed hardware components and an
auto-configuring capability designed into the system’s boot firmware allows the
system to deconfigure failed components and restore system operation. As long as
the system is capable of operating without the failed component, the ASR features
will enable the system to reboot automatically, without operator intervention.
During the power-on sequence, if a faulty component is detected, the component is
effectively disabled and, if the system remains capable of functioning, the boot
sequence continues. In a running system, some 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.
Note –
The ASR feature is not enabled until you activate it. Control over the
system’s ASR functionality is provided by a number of OpenBoot PROM commands
and configuration variables. For additional details, see Chapter 6.
Hardware Watchdog Mechanism
To detect and respond to system hang conditions, the Sun Fire 880 system features a
hardware watchdog mechanism—a hardware timer that is continually reset as long
as the operating system is running. In the event of a system hang, the operating
system is no longer able to reset the timer. The timer will then expire and cause an
automatic system reset, eliminating the need for operator intervention.