Oracle Sun Server X4-4, Service Manual

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Server Subsystems Overview
Sun Server X4-4 Overview 27
the fan modules fails, the other fan in the pair has sufficient power to cool the zone until the
failed fan can be replaced. However, if in the rare case that both fans in a pair fail, Oracle ILOM
will power off the system to prevent thermal damage.
Pressure Areas
The power supply and motherboard cooling areas have separate air pressures. The pressures are
maintained by a plastic divider that, combined with the top cover, creates a seal between the two
areas. It is important to maintain this seal because separate pressurizations for each area is the
key to maintaining the integrity of the cooling system and the health of the server.
Cooling Zones and Temperature Sensors
The two cooling areas are divided into four zones, one zone for the power supply area and three
zones for the motherboard area. Dividing the cooling into zones allows for greater use of system
resources, since each zone can operate independently at its highest efficiency. The zones are
designated from left to right (from the front of the server) as: zone 0, zone 1, zone 2, and zone 3
(power supply area). Temperature monitoring of each zone is accomplished using motherboard-
mounted temperature sensors.
The following illustration shows the cooling zones and the approximate location of the
temperature sensors. The accompanying legend table provides sensor NAC names and sensor
motherboard designations: