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cloaked_wolf
What's a life?
Joined: Thu Apr 23, 2009 8:46 pm Posts: 10022
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My workplace is out in the sticks. We get power cuts maybe every few months. Ordinarily it's not much of an issue. The power's down for a few minutes and soon enough we can get back to working.
More recently, the power cuts have become more frequent - a couple of times a month. The main issue is downtime. Our servers are connected to an online service. If it's down, we can't access the program for recording/accessig patient notes, blood results etc. Even though the power was off for a couple of minutes max, it can take 15-20 mins to be up and running again with the program.
I've suggested using an uninterruptible power supply which means the online connection isn't disturbed and hence we are only down for the few minutes it takes for the power to come back on.
What I'm looking for is some UPS units that can power two servers in one room, and the switches/routers in the cupboard.
Recommendations?
_________________ He fights for the users.
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Sun Jul 01, 2012 12:42 pm |
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jonbwfc
What's a life?
Joined: Thu Apr 23, 2009 7:26 pm Posts: 17040
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There's kind of more to this than you think. First of all, bear in mind all the desktop PCs that talk to your servers won't be on UPS, so if you lose power they will switch off anyway. It may be silly to spend money to keep a connection up that nobody has a working computer to use. Secondly, when you say 'servers', what do you actually mean? Desktop PCs running server software? Towers? Rack mounted kit?
What you need to do is you need to work out what 'pull' your servers & routing kit has (in terms of amps) and then you can decide exactly how big a UPS each will need. UPS's are rated in VoltAmps (which tell you how many devices they can supply at once) and KWH (which tells you how much total power they can supply), from which you can work out how long the batteries in a given UPS will last at the given VA.
So for example, a 1KWH UPS will keep a device pulling 10A at 100V up for an hour. Since UK power uses 240V (we'll call it 250 for ease of use), A 1KWH UPS will keep a mains powered device pulling 4 amps up for an hour, or two 4 Amp devices up for 30 minutes.
So what you do is figure out your VA from what the servers and kit pull, and then decide how long you want them to stay up for if you lose mains power. Thus you can figure out how many VA/KWH you need and therefore big a UPS to buy. There's no point paying money for a UPS if it will only keep your kit up for a few seconds (actually that's not quite true, but for the purpose you're suggesting it probably is).
In the main, battery UPS's keep server level stuff going for the order of 'a few minutes' - they're really there to allow for brown-outs and someone having to do limited work on power lines, and to give the servers enough time to shut down cleanly when the UPS senses mains power is out ( a lot of UPSes will connect to the server via USB, and when the power goes out the UPS tells the server to shut down to save it from possibly corrupting the data on it and keeps supplying power long enough for it to do so). If you want the stuff to stay up for more than 'a few minutes' you need a backup generator, not a UPS.
Course it's all down to your budget too. Heavy duty UPS kit is expensive (as well as being really really heavy) so it may be you have to say 'OK, we can only afford to keep kit running for a minute or two' and you have to live with it.
One thing - it's wise to use some of your power budget for at least one monitor (maybe a small low power LCD screen) and plug that into the UPS too. Place I worked at (which had a LOT of servers) plugged them all into UPSes but didn't bother/forgot to plug any monitors into the UPS. When a workman put a pneumatic drill through the power line outside that became.. inconvenient. Bad for us, worse for him mind.
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Sun Jul 01, 2012 1:25 pm |
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cloaked_wolf
What's a life?
Joined: Thu Apr 23, 2009 8:46 pm Posts: 10022
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Cool. That makes a lot of sense for a noob like me.
I need to have a chat with the boss about how long the power typically goes out for.
The two servers are desktop full-tower computers. They are always on and have a constant connection to EMIS. If the connection is broken, we have to faff around ringing them to re-establish the connection. This can take 15-20 mins. Hence if there's a power cut for even a few seconds, it can cause problems.
Hence by having a UPS that lasts say 5-10 mins, it should be enough to survive the power cut and hence ensure the connection is never broken. That way, we can turn the other computers on and continue working.
Is there anything else I need to know or find out About?
_________________ He fights for the users.
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Sun Jul 01, 2012 1:59 pm |
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finlay666
Spends far too much time on here
Joined: Thu Apr 23, 2009 9:40 pm Posts: 4876 Location: Newcastle
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You will need to know the power rating under load (as a worst case scenario) for the servers, then how long you need them for http://www.ebuyer.com/226810-apc-smart- ... a-smt1500iSomething like that for instance will only run for 7 minutes ar full load, but you may get 20-30 mins depending on the drain from the servers
_________________TwitterCharlie Brooker: Macs are glorified Fisher-Price activity centres for adults; computers for scaredy cats too nervous to learn how proper computers work; computers for people who earnestly believe in feng shui.
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Mon Jul 02, 2012 12:30 pm |
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cloaked_wolf
What's a life?
Joined: Thu Apr 23, 2009 8:46 pm Posts: 10022
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So had an extensive chat with the boss about various things, one of which was UPS - we have one. The precise one that Fin's linked to - paid for by the PCT. The problem is that other than my boss, no one has a frikkin' clue about IT stuff. The power cuts are usually much longer eg 30-60 mins and this is the problem - having a UPS that could last so long would be prohibitively expensive as we would be paying for it out of our own pockets.
_________________ He fights for the users.
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Mon Jul 02, 2012 4:13 pm |
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jonbwfc
What's a life?
Joined: Thu Apr 23, 2009 7:26 pm Posts: 17040
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You might still consider getting a small petrol generator (the things they have for caravans would probably do). They're relatively cheap. If the UPS can hold things up and running for a few minutes, that gives you enough time to get the generator fired up and patched into place (it would help if the UPS has two mains inputs, so you can leave the actual mains plugged in for when it comes back online - not sure for that model UPS though) assuming there's someone there who knows what to do anyway. You'd have to leave it running outside because of the exhaust but it might do the trick. Or just wait for a fuel cell generator to hit the market  . Jon
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Mon Jul 02, 2012 6:11 pm |
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cloaked_wolf
What's a life?
Joined: Thu Apr 23, 2009 8:46 pm Posts: 10022
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I discussed it with the partners (except my boss who is leaving and not interested). Told them to weigh up the cost vs the cost of downtime. They're not keen on the idea now.
_________________ He fights for the users.
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Mon Jul 02, 2012 6:42 pm |
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ShockWaffle
Doesn't have much of a life
Joined: Sat Apr 25, 2009 6:50 am Posts: 1911
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Welcome tot he world of IT. It's 90% about getting yelled at because a system is so important that it MUST have five nines availability (ie, must be up for 99.999% of the time), followed by sullen withdrawal of the same demand when you tell them what that would set them back.
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Mon Jul 02, 2012 7:45 pm |
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jonbwfc
What's a life?
Joined: Thu Apr 23, 2009 7:26 pm Posts: 17040
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The basic maxim of IT - 'you can have it now, you can have it cheap, you can have it reliable. Pick any two'.
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Mon Jul 02, 2012 7:58 pm |
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