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Adam
Asked: 2012-06-08 13:36:42 +0800 CST

Rack Mounting a Server with hot air vents on the top?

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We just got a couple of HP DL360 G7's, and I notice it has vents on the top. More hot air seems to exit through these vents than it does anywhere on the back. All our servers in the past have always vented all the hot air through the back.

How are these servers with top vents supposed to be mounted? Everyone always says airflow is best by not leaving gaps on the rack, but it seems like a server right on top of it would receive a lot of heat.

physical-environment hp-proliant rackmount

4 Answers

  1. Best Answer

    I really wouldn't worry too much about this. The HP ProLiant DL360 G7 has a small series of perforations along the rear 7-8 inches of the chassis lid (see the center-left of the photo below). This is just to provide ventilation for the full-height and half-height PCIe slots in the system.

    It's quite okay to stack these systems in a rack. Cold air is drawn-in from the front and exhausted out the rear of the chassis. ProLiant servers have a high thermal tolerance, so unless your systems are full of RAM + disks + PCIe cards and your ambient temperature is consistently over 85 degrees Fahrenheit (30 degrees Celsius), you're fine with the default BIOS setup. The system will adjust.

    NOTE - if any of the aforementioned do apply, there is a BIOS option to enable "Increased Cooling" that will force a higher overall system fan speed.

    DL380 G7 at top. Two DL360 G7 systems at the bottom enter image description here

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  2. Just follow the installation instructions, it's as simple as that. I know 380's way better than 360's but they can be stacked right on top of each other from the bottom to the top of a rack with no concerns so long as you follow th instructions and are within the rack's power/weight/cooling limits.

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  3. Heat will always rise. There is no effect on them if you rack them tight as the restricted airflow between servers will cause more draw out the back. That said, your server area should have as much cold air blowing on the front as possible. If you don't have a hot and cold row, you may consider running without doors and additional fans to improve airflow.

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  4. I suspect these are air inlets, not exhaust or outlets. The scientific term is venturi effect. Air passing the holes at 90 degrees will create suction and pull in additional cold air. If these servers are stacked without the 8mm spacing then the server will compensate with slightly increased fan speed. A demonstration (using water) can be seen here. https://www.youtube.com/watch?v=0ZMjDgM3LaU

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