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How Would You Build a Datacenter?
InOverOurHeads asks: "Some of my coworkers and I are building a new datacenter for our company. We're a growing startup, we have about 50 servers now and expect to have about twice that before too long so building to grow is key. Now that we're about $15,000 in to the project, it is looking and feeling more and more like we were way over our heads. We have 4 racks wired to a single 20amp circuit. Our UPS is at 90% load and we only have 10 machines on it. We have all of our cooling on one side of the server room where it is about 60 degrees, the other side of the room where the servers exhaust is about 30 degrees warmer, so it appears that we have some convection problems with only a handful of the machines on, right now. We're realizing that there is a lot more to building a datacenter than racking servers, what else have we missed?"
"On the positive note, we have a really nice overhead wire rack, that's looking good and all of our wiring is really tight looking; all the colors match, all the cables are labeled, they are all the right length, etc.
Are there any guides or how-tos on this? Since we're going to bite the bullet and tell the boss that we messed up we want to try
to correctly measure the rest of the work involved in making it work. What happens when the UPS is at 100% load and how Dell servers
react to being under powered?"
If the state of IT in this country is ay indication, your best bet is to fire everyone and outsource your needs to India.
But maybe I'm just bitter.
El riesgo vive siempre!
I know of four for sale in the denver area going for 1/3 to 1/2 what it cast to build one. They include redundant backbone connections, Power backup and great locations.
The best thing they are oversized, sell the extra space as a COLOC
Have no single point of a failure.Multiple UPS,network connections inside and outside, routers, firewalls, switches, etc. If anythinggoes down, you need to be able to replace it as quick as possible.
Are you in an earthquake zone (The Bay ARea)? If so, make sure 1, the building is earthquake retrofit, 2) the racks are all bolted to the wals suck that a little shake up doesn't turn into a shake down.
Make sure you are getting enough power to the building. Have Generators in case power goes out. UPS should only keep things going long enough for the generators to kick in.
Off site backups, of course. It is hard to beat the bandwidth of a stationwagon full of storage. Daily backups should be moved out of the building, I'd suggest on firewire/SCSI hotswappable hard drives, but there are many ways to solve this problem. Longer term backups should be a geographically out of disater range (east coast to west coast ideally)
Did I mention redundancy? Make sure you havea duplicate of everything.
OK, you have it built? Now test it. Kill the power and see if the UPSs can hold it long enough for the generators kick in. Now do it again, but pull out one generator.
Get one of those devices that allows you to remotely power cycle your machines as well, incase it locks up.
Havea back door (IE a dial up) to get into your data center unless you are going to have it manned 24/7. THis will keep you from coming in at 2 AM when a router blows.
Thats all off the top of my head. If I am wrong, please point out where, as the alternative viewpoints will be wuite helpful.
Open Source Identity Management: FreeIPA.org
Dont run everything off 1 UPS. You already stated you have 1 UPS at 90% of the load as it is. 1 Point of failure and the money you saved just caused a horrible outage and pissed off customers.
Sounds like you already know this, plan on secondary backup, AC, and make sure you have terminal servers. (Using unix right?)
You're definitely going to need a lot more AC and A/C.
You'll need at least one 20-amp circuit per rack in my opinion if you go with standard 110 battery backups. For that many servers though, you might be better off going with 220 service and the high voltage battery backups that APC and others offer.
Our old server room started small with a couple of servers and quickly outgrew the AC service and A/C. We heated our whole office in the winter with just the servers! Maintenance ran several new 20-amp circuits for us until we filled up the breaker box.
When we moved a couple of years ago, I made sure to get the new room right before we moved any equipment. We have central A/C fed by several outside units plus a very large auxiliary unit just for the server room. 20-amp circuits are ran every few feet on separate breakers. I don't know what type servers you are using, but large multi-processor, redundant fans, RAID, etc. boxes use LOTS of power. We use mostly Compaq DL380's, two of them will draw 50% off an APC 1400R battery backup. For extended runtimes, we made sure to not overload the battery backups, so only two servers per backup with no more than two backups per 20-amp circuit. It's slightly overkill, but I got very frustrated in our old location and resolved to never blow breakers or kill battery backups this time.
Since you're just getting started, it will pay off big time in the long run to get everything setup right before you start loading in servers. It makes things so much easier to just plug in without having to call maintenance or a contractor to upgrade services.
Jason
"FORMAT C:" - Kills bugs dead!
Have cool air coming up from the floor into each machine (and it'd be freezing)
Have a diesel generator with at least a few day's worth of fuel, and contingency plans for obtaining more fuel. It should be feasible to run on generator indefinately in case of a major power outage.
Redundant data centers. Have data mirrored between them for complete redundancy in case of any disaster striking one of the locations.
/. However, it would be worthwhile to specify the degree of importance and the budget of this project.
Obviously I am being facetious. If you had a budget and the necessity to do something on that scale, you wouldn't be asking
Ecce Europa - Web Design for Business
On the positive note, we have a really nice overhead wire rack, that's looking good and all of our wiring is really tight looking; all the colors match, all the cables are labeled, they are all the right length, etc.
"I don't care whether it works boys, just make it look good for the investors, ok?"
*shudder*
-Adam
On the off chance that this isn't a troll ($15 grand for 50 name brand servers, plus racks & UPS? It don't smell good here), did you guys do any research ahead of time, or did you just start slapping shit together? If I were your boss you would be FIRED, because you obviously have no clue as to what you are doing.
You obviously didn't talk to an HVAC engineer, because they would have set you up properly from the start, getting accurate heat output ratings for all the present and planned equipent (3.413 BTU per Watt, they tell me). Then, looking at the placement of the racks, would have had the cold air pumped in at the right places. This may be correctable by tossing a box fan or two in the room to move the air. Not fired yet.
You also didn't consult with an electrician or electrical engineer, because they would have given you some very sound advice on your load and UPS needs. You are so woefully underpowered and under-UPSed, your servers will lose power long before they have a chance to properly shut down. By the way, do you mean to say that you have 50 servers and only 10 are on UPS? FIRED!
"But look on the bright side, Mr. Boss, the cabling is all neat and pretty!" FIRED for spending more time on the cabling than you did planning this disaster!
Do the tech industry a favor, and go get a job shoveling shit at the zoo.
I assume you are not going to build a "datacenter", but rather build out a computer room. Given that here is what I have to say.
.7 . Computer volt-amps is really less than the volts times amps, due to complex impedence. Disk arrays are closer to 1.0 scaling. Don't skimp on power for disk arrays.
Don't build a computer room or datacenter. Find a commercial hosting service. Rent some cages and contract for reserving contiguous cages.
If you don't like the commercial hosting service here are the things I did to build out a computer room.
Power: Contract with a commercial electrician to get many more 20amp drops. The electrical contractor will know how to deal with the owners of your building to arrange the additional circuts. For most two processor intel boxes you can estimate 3 amps per box.
You can calculate the required volt-amps of your UPSs with this approximation UPSs volt-amps = Volts * AMPs *
Get rackmounted UPSs spec'ed out for the hardware connected to them. Don't skimp out here either.
Cooling: You can purchase "portable" air conditioners and put them in your computer room. They will drop the excess heat into your office ceilings; assuming you are in one of those buildings with popup ceiling tiles. Office buildings recycle heat this way so it is OK. Find out if your building turns off AC on the weekends and nights. I was at a place that did that, and it sucked working weekends and it sucked worse for our computers. If they do cut AC on the weekends, then you will need more BTU cooling from your portable air conditioning.
If you are really going to build a datacenter contract with an appropriate architecture firm. In my mind a "datacenter" is a basement or whole building with full on-site deisel power generators and raised floors or overhead wire guides. That is probably not something required for upto 100 hosts. Over 100 hosts is where that might be a good idea.
Did I mention that commercial hosting service? You may grow out of your office space with employees and want to move. A commercial hosting service provides far greater quality computer and network capacity, and the don't tie you down to much.
-- I am not a fanatic, I am a true believer.
A quick summary of your situation looks like this:
1. Hire an expert and do what s/he tells you.
2. Co-locate with a reputable site with excellent SLA's.
3. Continue on your obvious death spiral, and spend the cash on a great big party when you get fired (I give you about 6 months tops).
The first thing to do is hire someone that knows what they are doing. You are talking about a fairly small computer room-- they are often the ones with the most problems.
Some quick pointers:
-A single rack can be at about 2 kW with overhead air conditioning. Underfloor AC will get you closer to 3 kW. Much more than that, and you get in trouble. If you guess a real demand of 150W/server, you can fit about twelve servers in a single cabinet before you start to get into trouble. Plan for 5kW per rack on your UPS system and distribution - 2x20A outlets or 1x30A, 208V per cabinet (non-redundant)-- double for redundant cords.
-The back of the racks should be hot. That isn't a problem, in and of itself. Good data center design is based on hot and cold aisles for just this reason. To see if you have a problem with the air conditioning, check and see what the return air temperature is-- if that is too low (close to the cold aisle temperature), you are going to get stuck.
-If the backs of the racks are hot, make sure you have blank covers over all the open spaces on the racks. That keeps the hot air from mixing with the cold air on the front.
-If you have raised floors with AC, try putting a tile or two on the hot aisle to induce flow and make it more comfortable. That should help some of the hot air get back to the AC units.
-Have an engineer look at it. If you can, hire someone that specializes in data center design. Plan for at least $1,000/day of their time, $2k minimum-- just for looking at it and giving you a report. It's money well spent! You can bolt on a number of fixes for a problem, but it won't fix the root cause. Maybe that is good enough.
-Be careful of the breadbox UPS vendors. They want to bypass the engineers and the contractors. They don't always tell you what you need to know.
{shameless plug}I work for a company called Syska-- there's plenty of other companies that do this type of work though. {/shameless plug} Find someone close to you that can help.
The datacenter at my last job was about two thousand square feet and had on the order of 100 servers.
Some things that stood out for me were (I'm just a programmer, so this might be obvious you):
One rack was dedicated to what amounted to a switchboard. All the networking stuff was there. The wires running into the datacenter terminated in one set of ports (one pc, one port). These were then individually connected to a switch or hub using standard cabling. The servers in the room were wired the same way. Each station was hardwired to its set of ports on the switchboard. The idea was that it made it really easy to change the subnet of each machine w/o having to physically move it (just go to the switchboard and change the wiring). The internal telephone network (PBX?) was set up the same way.
There were the lab coats near the door. It was freezing. The AC units (I think there were 4-6 of them in the last place I worked) covered an entire wall. These were giant commercial ones. There was about two vents for every three aisles of machines. At the end of each aisle you could still feel the AC blowing.
The more expensive the machine, the closer it was to the AC.
The UPS covered about 100sqft in the basement and there was a diesel generator. Think the generator could run 15 hours on a full tank. Battery power was good for 15 minutes or so. There are about 300 pcs and monitors plugged in in addition to everything in the datacenter.
Orange outlets for clean (UPS) power, normal looking outlets for dirty power. The generator fed everything.
There was a control panel of some sort in the room where all the sysadmins sat. It had alarms for temperature and power and some other things I can't remember.
Hope this gives you some ideas.
You need help. (With an architect, I used to do this stuff for the "largest router company in the world".)
From an architectural perspective, don't underestimate the complexity of space planning. Equipment access, emergency egress, and growth of all engineering and supporting systems may put you at a very different place than you might imagine if you consider only your direct server capacity. I'm sure every geek around here would like to think they can solve most engineering type problems with a little extra effort, but building design has more than a few gotchas you don't want to miss.
On the building engineering side, the general trend is for higher and higher densities. Ten years ago, one might have projected that data centers would be getting exponentially larger, but the increasing density of electronic components keeps that growth more reasonable. However, density of equipment has a nasty side effect in that it pushes HVAC, power, UPS, and structural limits far beyond what your average spec office building is designed for. I know from experience that increasing structural floor load capacities from 80psf to 150psf is eyebrow-raising expensive with an operative data center!
Don't make dangerous mistakes. Beyond the expense, embarrasment, and possible job loss, you could create a serious life safety problem for yourselves or those working around you. Obviously four servers isn't exactly a major data center, but if that triples in the middle of a low load floor bay, (or if they're already some mondo racks) you might be closer to floor capacity than you realize. Sounds like you're beyond UPS, power, and HVAC load now--hire an architect with an engineer in tow for a few hours ($400-ish) to advise you. (Or mail me with your geographical location if you need recommendations. ;)
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