Sun Microsystems Fire 880, Руководство пользователя

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126 Sun Fire 880 Server Owner’s Guide • August 2001
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
■
SCSI bus
■
FC-AL subsystem
■
Fast Ethernet interface
■
Gigabit Ethernet interface
■
USB interface
■
Serial interfaces
The automatic system recovery feature 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 deconfigure 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 deconfigured 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” devices as either
failed or disabled , by
creating an appropriate “status” property in the corresponding device tree node. By
convention, UNIX 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, etc.), the system can be rebooted automatically and
resume operation while a service call is made.
Note –
ASR is not activated until you enable it. See “How to Enable ASR” on
page 130.