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I have to buy a stand alone server rack to be placed in a machine room. The temperature can reach 30°C in the room (I have no choice with regards to the location). In order to correct for this I will use active cooling with the used air being extracted.

I need to calculate the rating for the cooling cabinet. The cabinet will have 2 catalyst 2960 g switches and 4 HP ProLiant DL380p Gen8 E5-2609 2.4GHz 4-core 1P 4GB-R P420i SFF 460W PS Entry EU Servers as well as 3 USB extender receiver signal adapters.

The catalyst I can look up as well as the KVM but I have a problem with the Proliant as I cant figure out what heat it generates. The only BTU specification is the power supply which is rated in this case for 1725BTUs which is circa 506 watts. Does this mean that for four of these units I only need a cabinet that can cater for 4*(506)+2*(129)+3*(50) = 2.432 kW.

Can it be that easy?

  • 1
    My work used to run servers in very hot, dusty, and corrosive environments in our animal feed mills, until they discovered the stable reliability of quality switches running professionally installed fiber uplinks back to the sealed climate controlled office server room. The mills are now controlled with thin clients in the mill talking to the server room in the office that talks to the PLC's in the mill, both over the fiber link. It's worth the installation expense in improved availability for the mill. Just ask the manager in charge of your machine room how much unplanned downtime costs. – BeowulfNode42 Oct 27 '14 at 13:24
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This depends on your usage pattern, but I think your 2.432 kW number may be overkill.

In terms of your room's ambient temperature, the thresholds of the DL380p platform are:

  • Ambient temps warn at 42°C
  • Thermal shutdown occurs at 46°C.

This can be overridden/ignored, but that's a target to keep in mind. Here's the heat map and spot temperatures for a very busy DL380p Gen8 system described in detail below.

enter image description here

The BTU figure you see from the HP Quickspecs is a maximum, but we know that you won't be running these servers at full utilization. In a SMB scenario, It doesn't make sense to engineer for worst-case power/heat loads. These are extremely efficient servers and I've had success running them in less-than-ideal environments (warehouses, closets, bathrooms...)

However, HP does say: BTU = Volts X Amps X 3.41, so your calculation is correct.


Real-life power utilization figures...

For a DL380p with that spec (or slightly more powerful E5-2620 single-CPU configuration), with a light duty cycle I see:

System Information
        Manufacturer: HP
        Product Name: ProLiant DL380p Gen8

model name  : Intel(R) Xeon(R) CPU E5-2620 0 @ 2.00GHz
cpu MHz     : 2000.000

hpasmcli> SHOW POWERMETER
Power Meter #1
    Power Reading  : 62

hpasmcli> SHOW POWERSUPPLY
Power supply #1
    Present  : Yes
    Redundant: Yes
    Condition: Ok
    Hotplug  : Supported
    Power    : 35 Watts
Power supply #2
    Present  : Yes
    Redundant: Yes
    Condition: Ok
    Hotplug  : Supported
    Power    : 35 Watts

For an extremely busy DL380p Gen8 with TWO E5-2643 v2 3.5GHz CPUs, running with a 8 internal SAS disks, 192GB RAM, fully-populated PCIe slots and no power saving settings enabled, I see:

enter image description here

  • Thats a great answer thanks a lot! By the way what kind of server is there in a bathroom :) – DavyGravy Oct 26 '14 at 13:47
  • @DavyGravy Don't ask. I've tried to block it from my memory. – ewwhite Oct 27 '14 at 12:02
  • Ha Ha sounds rough! :) – DavyGravy Nov 5 '14 at 21:34

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