HP BladeSystem Enclosure technologies manual Thermal Logic for the server blade and enclosure

Figure 5. The c3000 Enclosure fan bay and device bay population guidelines

Thermal Logic for the server blade and enclosure

The server blade design uses precise ducting throughout the server blade to manage airflow and temperature based on the unique thermal requirements of all the critical components. The airflow is tightly ducted to ensure that no air bypasses the server blade and to obtain the most thermal work from the least amount of air. This concept allows much more flexibility in heat sink design choice. The heat sink design closely matches the requirements of the server blade and processor architecture. For example, in the Intel® Xeon® based HP BladeSystem BL460c server blade, HP was able to use a smaller, high-power processor heat sink than in rack-mount servers. These heat sinks have vapor chamber bases, thinner fins, and tighter fin pitch than previous designs. This allows creating the largest heat transfer surface in the smallest possible package (Figure 6). The smaller heat sink allows more space for full-size DIMM sockets and hot plug hard drives on the server blades.

Ducting produces high pressure, so the server blade uses less airflow and that reduces fan power requirements. The lower airflow requirement has the added benefit of optimizing available data center cooling capacity, which is one of the main issues facing IT facilities today and in the future.

Each device (server blades, interconnect modules, and enclosure subsystems) includes temperature sensors that monitor heat. If high temperature levels occur, the Integrated Lights-Outs (iLO) and Onboard Administrator modules provide alerts to various management tools such as Insight Control and HP Insight Manager. In addition, built-in failsafes will shut down devices in the enclosure if temperature levels exceed specified parameters. This prevents permanent damage to any devices within the enclosure.

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