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We are setting up a small 9U server cabinet in our office to house a single server along with a switch, UPS and some other miscellaneous components.

When the two fans are powered on at the top of the cabinet, the noise level is quite high.

since we only have a single low end server, we were hoping to not run the fans during normal business hours and then have them turn on automatically on a timed basis.

It seems that appliance times such as the ones folks use to have house lights turn on while they are on vacation might do the trick.

However, I wanted to post here to ask if anyone knew of a more elegant solution for our needs.

Ideally, we would like to have the fans turn on every 8 hours for so and run for about 2 hours and then shut down.

Are there any devices out there made for this kind of use? Or, can a UPS be programmed to dynamically shut off power to one of its power outlets?

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Thermostat/Controlled Fan

Sounds to me like what you REALLY need is a quiet fan that can move air when it needs to. The only real solution for the problem you're describing is a thermostatically controlled fan.

Here's an example of one for a server itself:

You can also find fans for server racks themselves but that starts to get expensive. Here's an example:

Depending on what your cabinet looks like... I think you should be able to come up with a cheap solution that does the job.

In either case... turning the fan on for 2 hours three times a day isn't really going to do much.

At the very least I'd try to find myself a cheap slow speed, low noise, high volume fan... something like this or perhaps even larger:

or this:

Once again... since I don't know what your cabinet looks like I can't really tell you if this is much help... but hopefully it gives you a few ideas.

Good luck.

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You may aswell not be using the other fan at all. Having it come on for 2 hours, every 8 hours, is utterly pointless and you're just wasting electricity.

If the unit was getting hot enough to need the second fan, you'd need it on all the time (or at much more regular intervals eg. on/off every 5 mins).

If the unit isn't getting hot enough, you don't need the fan.

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If you have a single computer in the rack, then the heat load is probably not too bad and you can possibly get away with not running the fans at all. If you don't have any sides/back/front on the rack, you can probably get away with not running the fans at all.

That said, if the rack is not adequately ventilated, you can damage components inside very quickly. Heat management is not something to be taken lightly.

At a couple of customer sites I've experienced total A/C failure, and in both cases every single piece of networking switch gear had to be replaced over the following year, plus several drives and even entire servers.

If noise is really a problem, you might want to see about buying some quieter fans. Most gear in "racks" is made for performance, not quietness.

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Some quieter fans that are thermostatically controlled might help. Take a look here, although I don't have personal experience with them or their products. You might also be able to reduce noise by reducing the physical coupling of the fans to the cabinet using sheets of neoprene between the contact surfaces if there's room.

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Not sure if it makes any sence to use the fans like you described, but a power timer may help, please check these links: 1, 2, 3

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Thanks all for the great feedback.

For the time being, our strategy will be to use one of these to simply turn the fans on and off manually. So, the first person to arrive in the office in the morning can turn it off and the last person to leave can turn it on. This way, the fans will run ~16 hours per day during the work week and non stop during the weekends.


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Why turn on the fans during the hours when there's no workload on the servers/components and they run naturally cooler anyway? Better go with huge and slow fans and use a thermostat. Heat management should be taken serious or you will need replacements within the first year. – hurikhan77 Sep 16 '09 at 22:56

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