servershutdowns wheninternal temperaturesexceed specification. Use cableties and otherwiring practices
tokeep the rear of the chassisunobstructed as shown in the “after“illustration.
Figure 14: Cable Management
253898
Before After
Airflow Considerations
Airflowthrough the chassis is from front to back. Air enters the chassis through the blade servers and power
supplygrills at the front of the chassis and exits through the fan modules on the back of the chassis. To ensure
properairflow, follow these guidelines:
•Maintainambient airflow throughout thedata center toensure normaloperation.
•Considerthe heat dissipation of all equipment when determining air-conditioning requirements. Donot
allowthe exhaust of one system to be the intake for another system.
•Whenevaluating airflow requirements,take into considerationthat the hot airgenerated byequipment
atthe bottom of the rack can be drawn in the intakeof the equipmentabove.
•Makesure that the exhaust at the rear of the chassis is unobstructed for at least 24 in. (61 cm).This
includesobstruction due to messycabling practices.
•Someblade servers ship with internal shrouds that are placed over the DIMMs and CPUs. They are used
tochannel airflow to where it is needed the most. If a shroud can be used a given model, it should be
used.
•Ifan enclosed rack is used, the front door must be 65 percent perforated to ensure adequate airflow to
theservers.
Cisco UCS 5108 Server Chassis Installation Guide
OL-20035-05 31
Installation
Airflow Considerations