Sun Microsystems Fire 880, Owner'S Manual

Page: 34 / 236

16 Sun Fire 880 Server Owner’s Guide • August 2001
Hot-Swappable Power Supplies
Power supplies in a redundant configuration feature a “hot-swap” capability. You
can remove and replace a faulty power supply without shutting down the operating
system. The power supplies are easily accessed from the rear of the system, without
the need to remove system covers.
Redundant, Hot-Swappable Fan Trays
The basic system configuration includes three primary fan tray assemblies to
provide system cooling. Systems equipped with the redundant cooling option
include three secondary fan trays for protection against cooling failures. Only the
primary fan trays are active during normal system operation. If a primary fan tray
fails, the environmental monitoring subsystem detects the failure and automatically
activates the appropriate secondary fan tray.
All fan trays feature a hot-swap capability. You can remove and replace a faulty fan
tray without shutting down the operating system. For additional details, see “About
Fan Trays” on page 75.
Environmental Monitoring and Control
The Sun Fire 880 system features an environmental monitoring subsystem designed
to protect against:
■
Extreme temperatures
■
Lack of adequate air flow through the system
■
Power supply problems
Monitoring and control capabilities reside at the operating system level as well as in
the system’s flash PROM firmware. This ensures that monitoring capabilities remain
operational even if the system has halted or is unable to boot.
The environmental monitoring subsystem uses an industry standard I
2
C bus. The I
2
C
bus is a simple two-wire serial bus, used throughout the system to allow the
monitoring and control of temperature sensors, fans, power supplies, status LEDs,
and the front panel keyswitch.
Temperature sensors are located throughout the system to monitor the ambient
temperature of the system and the temperature of each CPU. The monitoring
subsystem frequently polls each sensor and uses the sampled temperatures to report
and respond to any overtemperature or undertemperature conditions.