The airflow in of all components of an HCP system is designed to go from front to rear and is driven by fans on the various components. Air is pulled through the front of the rack and exhausted out the rear of the rack. Components mounted in the rack, such as Ethernet or Fibre Channel switches, have port side exhaust in keeping with the overall rack airflow. Customers should not reorient the devices in the rack or the airflow may be compromised.
The following table shows the heat dissipation for each of the components, allowing a customer to calculate the heat load and required cooling for their HCP system based on the components installed. It also includes the acoustic noise level of the fans in the units which are providing the airflow, where this information is available.
| Component | Heat Dissipation (BTU/h) | Acoustic Noise Level (dB) |
|---|---|---|
| HCP G11 Node | 894 | N/A |
| Brocade ICX 6430 | 67 | 0 (Fanless) |
| HP 4208VL | 2152 | 64.2 |
| Brocade VDX 6740 | 597 | 63.1 |
| Cisco Nexus 5548 | 1331 | N/A |
| Cisco Nexus 5596 | 2252 | N/A |
| Brocade 6510 | 375 (typical) 420 (maximum) |
70 |
| Cisco MDS 9148S | 183 | 60 |
When a number of the HCP system components are powered on, the fans run at full speed for a short time to ensure that they are fully operational. After that, under normal conditions, the fans run at lower speeds as required by the device for maintaining appropriate airflow and cooling to the components. The cooling they provide is sufficient to prevent the hard disk drives and other components from exceeding the manufacturer’s rated specifications throughout the range of the operating conditions. If overtemperature conditions occur, some of the devices have automatic shutdown capability, but not in all cases.
If a single fan fails in any of the HCP system components, the device continues to operate. However, this fault condition forces the remaining fans to run at higher speed until the condition is corrected.