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Cooling Autonomics: Dynamic Impedance Control for Blades - "Smart Blades" Disclosure Number: IPCOM000033492D
Original Publication Date: 2004-Dec-13
Included in the Prior Art Database: 2004-Dec-13
Document File: 5 page(s) / 83K

Publishing Venue



In today's blade server environment in thermally redundant modes (one of two blowers in the failed condition), there exists the requirement to throttle all processors to a power level where sufficient cooling is possible. This does not allow customers to fully utilize any of the 14 blade (if fully populated) due to reductions in power yielding reductions in frequency. There is no solution to this issue. There are limits to the performance of thermal solutions (AMDs and heatsinks) which are exceeded in thermally degraded environments in confined volumetric such as in the blade space.

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Cooling Autonomics: Dynamic Impedance Control for Blades - "Smart Blades"

     The invention is a "Smart Blade"; a blade that can create an impedance within itself or near itself restricting the flow through the blade in order to direct more airflow through one or multiple highly stressed blades.


     Currently, in a redundant mode, all CPUs in all blades are required to be throttled in order to cool to specifications, regardless of what is happening with specific blade CPUs. Invention will allow for a blade to understand it's power state through various temperature monitors and have to ability to reduce it's airflow, sending more to struggling blades, eliminating the need of forced throttling.

     Invention can also be used in normal operating modes to reduce possible throttling events.

     Each blade in a BladeCenter will be designed with the hardware and the code to create high impedance sources in close proximity to itself (within the blade or directly behind it). The "Smart Blade" would be capable of monitoring various temperatures (component and free stream) which would be compared to a code table. This comparison would allow the blade to know if it is running cool or warm. If a blade is running cool, the cooling would be reduced for blade. This means high stressed blade(s) will have a higher percentage of available airflow. Eventually cooling equilibrium would be reached.

About the Diagrams:

     Figure 1 illustrates the airflow path within a BladeCenter server. Air is drawn through the entire system via two high speed blowers seated in the rear of the chassis. Air enters each blade through perforations before passing over CPU heatsinks, memory, HDDs, and other components within the blade. The air exhausts each blade at locations 1, 2, and 3 shown in the figure. Approximately 50% of the blades airflow is exhausted through the rear of the blade, location 3. Most of the airflow exhausted out the blade at location 3 will makes its way to the blowers via openings in the midplane, location 4 in the figure. Airflow that travels through locations 1 and 2 will continue towards the rear of the system along the top and bottom wall before it enters through the power supplies or switches which are in the foreground and background of the blowers shown. All of the airflow will find its way to the plenum between the two blowers, location 5. The blowers then exhaust the airflow out of the rear of the system.


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Figure 1: BladeCenter with arrows showing airflow direction

     Figure 2 shows a potential BladeCenter midplane. One this midplane, there are 14 pairs of connectors which mate with an inserted blade (not shown). Between each pair of connectors (upper and lower connector), there is an opening in the FR4 board (location 4 in Figure 1). Each opening is where roughly 50% of the airflow through each blade is exhausted.

Figure 2: BladeCenter mid-plane

     Figure 3 shows a BladeCenter server running in a normal mode of operation with two functional...