IBM 88861TU, Planning Manual

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Airflow considerations
Air flow is critical for ensuring the operating air temperature stays within
permissible limits.
v
Each BladeCenter S system requires a maximum of 450 cubic feet per minute
(CFM) and a minimum of 200 CFM of air circulation.
v
Each BladeCenter S system has four fan modules, each containing two fans, for a
total of eight fans.
v
Each power supply contains fans that are used to cool the storage modules.
v Airflow direction is from front to back.
v
All BladeCenter S chassis bays must be populated, either with a module, a blade
server, or a filler in place of the component.
v
All equipment installed in a rack with a BladeCenter S system must use
front-to-back airflow to prevent warm-air-recirculation problems. Devices that
use back-to-front air flow cause warm air to enter the front of the BladeCenter S
chassis. This can cause reduced reliability, component failure, data loss, or blade
server shutdown.
v
In racks with multiple BladeCenter S systems, populate the BladeCenter S
chassis starting with the bottom chassis in the rack and working up towards the
top of the rack.
v
Any unused rack space must be covered with a blank rack filler panel to ensure
proper air circulation.
Heat output
The amount of heat output from a BladeCenter S system in British thermal units
(BTUs) per hour is based on the configuration.
v
Minimum configuration: 1365 Btu/hour or 400 watts
v
Maximum configuration: 11942 Btu/hour or 3500 watts
Prevention of air recirculation
Consider these air recirculation factors when planning for single or multiple rack
installations.
v
When racks are positioned adjacent to each other, ensure that the racks fit tightly
together from side to side to prevent inter-rack air recirculation from the back to
the front.
v
Air recirculation occurs over the top or around the side of a rack in a room that
does not have a cooling system with sufficient airflow volume capacity. Ensure
that the cooling system has adequate capacity for the room cooling load.
Room cooling
To prevent possible BladeCenter S system thermal failures, proper room cooling is
vital.
v Ensure that the site cooling system has adequate capacity for the room cooling
load.
v
Ensure that cool air is provided to the front of the BladeCenter S chassis and
rack.
v
Ensure that the room cooling system is positioned so warm exhaust air is
directed away from all BladeCenter S chassis towards the room cooling system
without passing in front of a BladeCenter S chassis.
v
A significant air temperature gradient can occur from the bottom to the top of a
rack in a room that has a cooling system that does not have sufficient airflow
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BladeCenter S Type 7779/8886: Planning Guide