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UPS advice

Sorta Oldguy

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I've been going commando so to-to-speak with my server with respect to a ups and have so far lived to tell about it. Am adding bigger drives and some a-b comparisons on the old setup switching on and off write caching show a huge difference in performance. Was always afraid to turn it on since I had never gotten around to getting a ups. But the tests convinced me write caching is worth more than faster drives. See attached. I've been seeing the lower end of the tests. Works fine for streaming but copying things on is very slow.


Anyways, I have no idea how to figure how big a unit I need. All I need is something that will last long enough for an automatic shut down and software that will run on Windows Server 2012.The makers of UPS look like they try to steer you into big honking units that are overkill. Would appreciate links to reliable calculators or comments.


What I have is an Antec NSK-6582 case that comes with an Antec EA-430D Green ps that has PFC. Asus P8H67 motherboard, 24GB RAM, a 256G SSD, a 1T Samsung drive, and will have 4 3TB drives (3 WD Reds and on Green til I can get another on sale). The machine really loafs along, with pretty low cpu usage and almost never reaching 45 degrees C.



write caching.pdf

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  • cskenney


  • ikon


  • Sorta Oldguy


  • schoondoggy


1000VA seems like overkill to me. You could go with one about 1/2 that size and still probably have 10 minutes of run time for it to shut down.


Have you looked at the calculator on the APC site? It might help you size a UPS. http://www.apc.com/tools/ups_selector/


Thanks for the link. Went through it and it came up with APC Smart-UPS C 1000VA LCD 120V. Claims 17 min runtime but $300? Whew!.


Do you think it would do any good to get one of the those inexpensive power meters I've heard mentioned on the BYOB podcast to do a direct measurement under load?




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The APC config tool points to a 750va to give 10 minutes runtime. A 750VA APC is $100, a 1000VA is $140. If you are only going to run this system a 750 would be fine.

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Guest no-control

No offense to CSK but that APC calc is trash.


Investing in a UPS is a tough decision when you do not have a lot of PC's. While 1000va maybe overkill that is usually the sweet spot in terms of price. Costco usually has 1000va units for about $99. Fairly cheap IMO. But before you go there couple of things to consider...


First, what equipment exactly do need a PSU for? Just a server? Why not the modem, router, and switch? Is there a monitor involved? What about coax, phone, data and other infrastructure?

Second, any specific features you need? If not then this is an easy one.

Third, budget? How much are you wanting to spend?

Fourth, Finally location & electrical stability? If geographically you are prone to lighting strikes, brown/black outs, surges and spikes, natural disasters, etc...you may want to buy something more robust.


Calculating the size is pretty easy. Here's how I do go about it.

  1. List the power input ratings of all equipment you want to protect. I do this separately for either Watts or Volt Ampere. Volt Ampere rating preferred if it's available.
  2. Find the watts or Volt-Amperes (VA) numbers for the devices you want to connect, including any power strips. Usually you can find them on the power brick or transformer plugs This will be you minimum requirement usually you want 25-30% reserve for slow systems and future expansion. If Volts and Ampere are stated individually, multiply them to get the VA. If the input voltage is variable use the smaller number. (low voltage means high current; high voltage means low current; the maximum current is stated, use the low voltage for your calculations.) Always look at the input ratings of the equipment.
  3. Divide subtotal for Watts by 0.6 and add it to the subtotal of the Volt Ampere. The result is your total VA requirement

For example, here is my rack setup:

Switch = 14.0

Firewall = 16.0

WAP = 9.0

Printer = 13.0

Modem = 7.3

M-Cell = 8.9

obitalk = 3.6

Total = 71.8 VA


My server I will measured in Watts for this example.

Server = 105 W <- full load @ start up


Formula is VA+W/.6 = VA Required

71.8 VA + 105/0.6 VA = 246.8 VA


I like to have a 30% buffer so


246.8 + 74.04 = 320.84 VA


Since my requirement is 321VA I could get away with something in the 330-350 range. I'm actually using a 500VA just because of the amount of equipment I cycle through and since I wanted a rackmount with a readout I bought this cyberpower unit.


My workstation also has a UPS I bought from Costco its 1000VA for $99. Why 1000VA? Well because my primary rigs tend to be freaking ridiculous, and I plug my entire setup (monitors, receiver,etc...) in to it...plus it has coaxial I/O so i use that to isolate the network from the outside world.


Buying a Kill-A-Watt make adding everything up a snap.


Happy shopping.

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No offense to CSK but that APC calc is trash.


No offense taken. The APC calc is going to try and up sell you to a unit larger than you need.


For reference I am running my mediasmart server, router, switch and 2 HDHR's off of one 550VA UPS.

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No one seems to have mentioned it yet, but have you considered a True SineWave UPS? They're almost a requirement for the newer PFC power supplies. The lowest priced ones I've seen are from CyberPower. Normally, a true sineware UPS costs way more than these ones. I have a CyberPower 1000PFCLCD unit supporting my WHS2011 setup. Here's a link to a shot of it: http://homeserversho...2_35_361703.jpg.


If you look at the photo, at the far left of the top shelf you can see the UPS. Next to it are 2 Lian-Li EX503 boxes. They each have 4 low power (i.e. 'green' type 5400 RPM) drives in them. On the shelf below you can see a small USB powered fan at the left, a drive in a toaster dock, and finally the server itself. The server is a Core2Duo with 6 drives: 2x256GB mirrored for the OS and 4x2TB in RAID5 for the data. That's it. There isn't even a monitor. I can hook up a monitor, and do from time to time, but even then it's not plugged into the UPS.


That UPS gives me 3 - 5 minutes of battery time. Believe me, I've tested it. Basically, it's enough time for the server to do a graceful shutdown.


I'm not sure why the UPS doesn't give more battery time. I've certainly had other more conventional square wave UPS units that had less VA but still gave more battery time. I put it down to the fact that the UPS puts out true sineware AC.


Nevertheless, and despite the short battery time, I would rather have this unit supporting my server. I feel the true sinewave AC is worth the tradeoff.

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I didn't expect the deluge of help within a few hours, but I guess that's what makes this board nice. Want to thank everyone for the suggestions. Actual examples of what you use are pretty helpful and I imagine it will be one of those. My setup doesn't seem any more powerful than what others are using.



No-control: didn't expect you all to make me work :) Means I'll have to get up out of my easy chair and go walk back there and look at stuff. I really don't have much in the way of peripherals: a cable modem and cheap Rosewill dual band wireless router that works very well for the price. Have a monitor hooked up to the server but only use it when necessary. And I generally don't keep the printer on unless it's being used. Control the server and the VM's via remote desktop. There's no wired networks here; we are renting.


ikon: nice picture. I suppose it was taken in one of those yankee dwellings where they have basements. Having lived on the Gulf Coast all my life, I can't remember ever being in the basement of a residence.



Since I have a green power supply with PFC I may spend a little extra for a sine wave. Model.


This brings me to another question: does the UPS come with software to do the shutdown, or does Server 2012 recognize the UPS when you plug it in and the serve installs it's own drivers?

Edited by Sorta Oldguy
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