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Running a few computer servers in my home, is it safe?

6K views 54 replies 12 participants last post by  beenthere 
#1 ·
Hi, i'm a computer programmer but when it comes to electrical stuff I have no clue what I'm doing. I'm trying to figure out the safety of my soon-to-be server farm setup.

I have a room where I want to run a few computer servers totaling about 1760 watts 24/7. My biggest concern is the 1250W server. Will my outlets handle it? How can I check? I just used a kill-a-watt with a 1875W blow dryer and its actual usage was about 1519W.

Does this mean I could use about 1500W 24/7 safely? I would then move the smaller servers to another room, if this makes a difference?

Thanks!
 
#3 ·
I took some pictures, I'm guessing I need to figure out which circuit my server room is connected to right?

I don't know how to verify this without turning off each circuit right now, so could we assume the lowest... 15 amps?
 

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#4 ·
... a few computer servers totaling about 1760 watts 24/7. My biggest concern is the 1250W server.
First, what was the source of that 1760 watt number? Are those nameplate numbers? Or did you actually measure the servers while in operation elsewhere? The reason I'm asking is that nameplate values are typically overstated by about 50%. That applies on Dell, HP, etc. If those are nameplate values, you'll be able to get by on quite a bit less. Our nicely-tricked-out Dell R710s, for example, generally run less than 500 watts.

And don't forget the UPS/surge suppression. If they're servers, you'll want them to stay up, at least through the momentary power glitches.
 
#6 ·
Most of these servers are purpose built servers and not the typical server. The wattages are accurate readings on full load (normal operation), which was from its performance testing.

The 1760W is the single 1250W server plus a few others I just added on.
 
#8 ·
If your panel isn't labeled to identify which breakers support different areas of the house then you need to do that. Turn everything off in the house, then turn off one 20 amp breaker and plug the light into each outlet until you find all that are dead. Then turn that breaker on and the next one off and repeat. It won't take that long to map out the house.
If your server room shows to be a 20 amp breaker, that will support 2400 watts but only plan to load it to 80% or 1920 watts. Use your Kill a Watt to see what your servers actually draw for power. As mentioned already, that number on the back is that maximum the server is capable of drawing. The current draw is dependent on how much memory is installed, the number of HD's, the number of plug-in cards and what ever else can be connected. It also depends on what board and processor are installed that the power supply has to support.
 
#10 ·
Alright so a 20 amp can handle 1920W and 15 amp can handle 1440W?

I guess I'll have to map the house tomorrow so I don't get yelled at when everything is in use :laughing:

As far as the server usage, they are purpose built and will be running full load at the numbers I mentioned above, unless I tweak them lower. These are number crunching machines working 24/7 :)
 
#12 ·
Okay, right off the bat you're going to have some heat load problems in that room. And probably an APC SmartUPS 1500 (~$500, IIRC) or equivalent. If you want everything on UPS, you might be looking at a 2200 (~$1k). Unfortunately, that's a fair chunk of change. And your HVAC solution will probably be another chunk. I run a data center for a living and it's not a trivial task to set up a good home server room. 100% of your power will effectively be converted to heat and blown into the room. What kind of budget constraints do you have?

And gregzoll has a good point - a single server with multiple VMs might be a good alternative to multiple machines.
 
#13 ·
Okay, right off the bat you're going to have some heat load problems in that room. And probably an APC SmartUPS 1500 (~$500, IIRC) or equivalent. If you want everything on UPS, you might be looking at a 2200 (~$1k). Unfortunately, that's a fair chunk of change. And your HVAC solution will probably be another chunk. I run a data center for a living and it's not a trivial task to set up a good home server room. 100% of your power will effectively be converted to heat and blown into the room. What kind of budget constraints do you have?
Not a lot? I honestly did not think of how bad the heating would get. Maybe a couple hundred dollars max.

Note, these servers will only be on my local network and inaccessible from the internet (assuming no one hacks me :mad: ). If I loose power, it is OKAY to shutdown within minutes (with cheaper UPS). More important is having surge protection.

So maybe I could still split the servers into two rooms to separate power load and heat? Does this sound reasonable?
 
#17 ·
I didn't want to get into the details of my setup since the concern is mostly about the electrical usage, it's safety, and heat produced from ~1760W, so I called them servers when really they're devices. But thank you guys for your suggestions on using virtualization! :D
 
#21 · (Edited)
mpoulton, do you even have a clue in what VM's can do? They can do the same as running a conventional computer, and can take advantage of the multiple cores, along with the RAM available. Especially if the person setting up the VM on the server knows what they are doing. As for what the OP is doing, it is nothing in the line of what a Supercomputer would do, due to from the sounds of it, they are doing some type of distributed computing, which was a fad five years ago, but is starting to fade. Especially in the past three years.

You may want to give this a read. http://itbusinessnet.com/article/Distributed-and-Cloud-Computing-1720627
 
#24 ·
Are you planning on locating these servers in a spare room, or in space that you plan to actively use? If the former, you might want to look into the research on the failure rates vs. ambient temperatures of the data centers. That'll give you an idea of around what temperature you should keep the room at.

You may also want to look at shelling out at least a little bit more for a better UPS. Many proper UPSes, even the cheap ones, have either a ethernet or serial connection that allows them to tell the protected computers to automatically shutdown on power failure.
 
#26 ·
They'll be in a spare room. The UPS I posted earlier won't be used for this. I will get a new one.

Thanks for the tips on temperature. Looks like 72-80F should be a target. With my a/c set to 78 during the summer, I think adding a portable cooler should suffice. I'm looking at evaporative coolers now, apparently they work best in dry and hot areas. Hey! Arizona + Server room :D
 
#32 ·
Sorry been out all day.

There are two rooms that share the same circuit. Luckily these two rooms are my spare rooms. The circuit is the far bottom right labeled '15'. Which I'm guessing means my limits are 15a and 120V (V reading from my kill a watt). So my max is 120*15*0.8=1440W. Correct me if I'm wrong.

Unfortunately these are the two rooms I wanted to split my hardware. I could ensure nothing is plugged in the other spare (guest) room, but that would be a hassle for my guests.

I was thinking, maybe I could ask the landlord (which is actually a company) if they could put my server room on a dedicated 20a and leave the other room on the 15a. Would this be feasible with the existing infrastructure?

Any other ideas?


 
#31 ·
Okay, unless I've forgotten my math skills, a 1760 watt load on a 120v circuit will pull right at 15a. (That's neglecting power factor, which for most modern equipment is just about 1 anyway.) You can't pull 15a on a 15a circuit continuously - that's a no-no. Figuring in an 80% derate, that'd mean you'd need an 18-and-change amp circuit, so you could get by with a 20a circuit providing there wasn't anything else on that circuit.

The optimal solution would be to bring in a couple dedicated 20a circuits, but since you're renting that's not an option. Personally, given your situation, I'd split the load and use two sets of equipment and two UPSes on two different circuits. That would also halve your heat load in any given location, which might help. Being a renter kinda limits your options... Do you have a friend with a house and a broadband connection that might be able to colo your equipment?
 
#33 ·
Yeah I think I need a dedicated circuit, see my last post. It could be an option if I had approval from the landlord and paid for it myself. I'm guessing $100-200? The electrical panel is on the other side of my server room, if this makes any differences on installation costs.

I really don't want to leave my equipment with a friend. I'm just too afraid it would get damaged.
 
#34 ·
You would need a little rewiring. You would have to fish a wire for the new circuit to one of the existing outlets, then disconnect the rooms from each other.
 
#35 ·
Also, is there a limit on power usage for all circuits combined?

My a/c, washer, dryer, water heater, kitchen appliances, etc are all on their own circuits, but does running them all at the same time have any affect on my electrical line?

I was just imagining a hot summer weekend where we're washing clothes and cooking up lunch and the servers are running.
 
#36 ·
Getting back on topic.....

1750 Watts will generate about 5971 BTU's of heat....

If you adding up the max power on all the servers to come up with your total wattage.....chances are you will never see it....

I would see if you have two ckts in the room...as in outlets fed from 2 different breakers...if so, get two UPS's and run 2 servers on each one with the servers plugged into seperate outlets.

As for the 'number crunching'....I'm guessing that he is running a ****o site and the 'numbers' are the number of perverts logged on....
 
#37 ·
Ah nice, I didn't you could calculate BTU from W.

I checked all outlets in the two rooms and they all share the one circuit.

This is not a ****o site or any website. Like I mentioned earlier they are inaccessible from the internet. And this is nothing illegal! Sigh, I just want to provide the important details and anything beyond the wattage of my devices aren't.
 
#38 ·
Since both of your possible rooms are on the same circuit, and it's only a 15a anyway, I would think your best solution is to contact your landlord and see if you can have an electrician drop in a dedicated 20a circuit. (Assuming you're going to be there long enough to make it worthwhile...)

You say your panel is in one of the rooms. That might make it real easy to install an outlet under the panel and just drop a short feed from the panel to the box. Plug your UPS into that outlet and run a power strip with a long cord along the baseboard over to where your equipment will be. Caveat: I'm not an electrician so I don't know if it's code-compliant to put an outlet directly under a panel, so one of the board's Sparkies would have to chime in here. But it sure would minimize the amount of fishing/time/expense involved. And I'm pretty sure from reading these boatrds that commercial property must be done by a licensed electrician and with the landlord's approval. And I might just be sure to get that approval in writing... :)

PS: Some people just aren't worth paying attention to...
 
#39 ·
The panel is on the other side of the wall (outside) so I would have to embed the wiring in the wall.

I'll call my landlord on Monday and ask if I could add a 20A outlet, with written approval and ensure it's done by a licensed electrician. -Thanks

Hopefully this works out and I could plug the 1250W and cooling unit to the 20A outlet, then the rest of the lighter devices on the existing 15A outlets.
 
#46 ·
You guys are looking at the cooling situation all wrong. Keeping the room cool with an ac unit is going to be in the 1000 dollar a month for electicity range between the computer and hvac. The way to go about it is to build an enclosure at the window so cool air is sucked through the house, runs through the computer and the hot air is exhausted out the window.
 
#53 ·
Jimmy21,
Without getting into the thermodynamic details, it's easier to move heat from point A to point B then it is to create heat. Thus the AC can be sized smaller than the heat generator. To get energy star rating an AC unit needs to move ~3.2 units of energy to the outdoors for every unit of input energy (assuming outdoor temp of 95F and an indoor temp of 80F).

If you're curious, here's how I came up with the 3.2 number:
- Energy Star requires AC units to have an Energy Efficiency Ratio of 11 (or 12 depending on the type of unit)
- EER is in the oh so helpful units of (BtuH/Watt)
- Wikipedia has the formula for the conversion from EER to the Coefficient of Performance (COP)
- COP is in the helpful units of (Energy Removed / Energy In)
- The formula is EER = COP * 3.412
- Thus ACs need a COP of 3.22 (or 3.52 for certain types) for an energy star rating
 
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