B, C, and D represent genuine failure or degradation conditions. A sensor fault can impair detection and control response even if the mechanical equipment itself remains available. A cooling unit that stops while supply temperature rises is a direct equipment/cooling-capacity failure. Poor airflow producing localized hot spots is also a cooling-system performance failure because cooling effectiveness depends not merely on operating equipment but on delivering conditioned air to the IT intake and preventing exhaust recirculation.

Oracle requires adequate front-to-back airflow and warns that gaps, obstructions, and inadequate cold airflow can adversely affect cooling. Oracle also states that environmental conditions are not uniform across a data room and recommends monitoring at multiple points. Excessive rack temperature can decrease hardware reliability and ultimately lead to partial or complete shutdown.

A, E, and F describe expected or stable operation: supply temperature is near setpoint, system status and temperature are stable, or airflow and rack inlet temperatures remain within range. The key operational concept is that cooling failure can arise from equipment loss, control/sensor degradation, or airflow-distribution failure , not only from complete chiller or cooling-unit shutdown.

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