68 Sun Fire 280R Server Owner’s Guide • January 2001
Power Supply Redundancy
The system can accommodate one or two power supplies. All system configurations
can operate with only one power supply installed. Youcan use a second supply to
provide redundancy,enabling the system to continue operating should one of the
power supplies fail. When both power supplies are installed and functioning, they
share the power load. For more information about power supplies, redundancy,and
configuration rules, see “About Power Supplies” on page95.

Hot-Swappable Power Supplies

Power supplies in a redundant configuration feature a hot-swap capability.A
qualified service provider can remove and replacea faulty power supply without
turning off the system power,or even shutting down the operating system. A
redundantpower supply can also be added to the system without shutting down the
operating system. The power supplies are easily accessed from the front of the
system. For information about removing and installing a power supply,see the Sun
Fire 280R Server Service Manual.
Automatic System Recovery
The system firmware providesfor automatic system recovery (ASR), which enables
the system to resume operation after faults or failures that cause a system reset.
Recovery from a system reset is automatic fromthe operating environment level for
the following types of failures:
■Operating environment failure
■Intermittent transient hardware failure
If the operating environment software hangs or crashes, the system is configuredto
automatically reboot and for the operating environment to resume.
In a running system, some types of hardware failures (for example, intermittent
transient memory errors) can shut down the system. If this happens, the ASR
functionality enables the system to reboot immediately.
Automaticself-test features enable the system to detect failed hardware components.
During the power-on self-test (POST) sequence, if a faulty hardware component is
detected, the boot sequence halts at the ok prompt. A full suite of diagnostic
software is provided to diagnose such failures (see the following section for a
summary of these software tools, and Chapter6 for information about using these
diagnostic tools).