Sun Microsystems Fire V890 Service Manual page 263

Primary I/O fan tray
Secondary I/O fan tray
Only the primary fan trays are running during normal system operation. If a
primary fan tray fails, the environmental monitoring subsystem detects the failure
and automatically activates the 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 or turning off the system power.
For additional details, see
on page 6.
For each fan in the system, the environmental monitoring subsystem monitors or
controls the following:
Fan present (monitored)
■
Fan speed in revolutions per minute (RPM) (monitored) – Used to detect early fan
■
degradation
Fan power input (controlled) – Used to increase or decrease the airflow and
■
cooling capacity
Fan fault LEDs (controlled)
■
Only the primary CPU fans have variable speed control. The secondary CPU fans,
the primary and secondary motherboard fans, and the primary and secondary I/O
fans can only be turned fully on or fully off. Fan speed is controlled by the
environmental monitoring subsystem in response to temperature conditions inside
the system. For additional details, refer to the Sun Fire V890 Server Owner's Guide.
Primary CPU fan tray
Secondary CPU fan tray
"About Hot-Pluggable and Hot-Swappable Components"
Secondary motherboard fan tray
Chapter 7 Hardware Configuration
Primary
motherboard
fan tray
235