Servers

Selecting and installing your first UPS

As an IT professional, you see UPS (Uninterruptible Power Supply) just about everywhere. Every server room will likely have one of these somewhere. Datacenters are filled with banks of them. Yet there is not much that is written about these boring, yet essential, pieces of silent (literally!) hardware.

As an IT professional, you see UPS (Uninterruptible Power Supply) just about everywhere. Every server room will likely have one of these somewhere. Datacenters are filled with banks of them. Yet there is not much that is written about these boring, yet essential, pieces of silent (literally!) hardware.

Drawing on my own experiences, I've come up with three simple steps for the newbie making their first UPS purchase.

1. Size up your battery capacity

The first step in any UPS installation would be to first size up your requirements and identify the servers that you intend to connect to the UPS. While trying to match the correct UPS model to your server isn't that complicated, it can be overwhelming if you are not a hardware type of person.I will detail how to compute approximate power requirements in a later article, but my advice to the novice is to pass on this part to your vendor for their advice. Some manufacturers like APC will gladly field such enquiries and give you exact recommendations if your servers are fairly mainstream brands, and you are able to furnish them with the model number of your servers.

For simplicity's sake, I group UPS into three installation "sizes" -- small, medium, and large.

  • Small: Low-capacity UPS that is normally used to power a couple of desktops or a single server. These can be easily purchased off-the-shelf.
  • Medium: Any UPS that is designed to serve more than a single server, yet still plug-and-play. These have to be purchased from IT equipment vendors.
  • Large: Any UPS that cannot be directly powered off of an unmodified wall socket is classified as "large." Also, unless you have prior experience with electrical matters, you should get the engineer from your UPS manufacturer to come in, or else engage the services of a qualified electrician. These UPSs tend to be available only from the manufacturers themselves, or from select vendors.

Most server rooms will probably consist of a number of medium-size UPSs. They might run independently, or are cascaded with battery packs to prolong runtime. I am generalizing here, but two or three of these is usually sufficient to support a rack of equipment.

2. Determine the best location

Unless you have a very good reason not to, you should always install your UPS at the bottom-most section of your server racks. The primary reason is that UPS are heavy beasts, and it makes sense to place them as low as you can.

Some UPSs come with adjustable rails, allowing you to easily slide the UPS in and out of your server rack. Should you use them? Well, feel free to go ahead if your vendor offers free installation. Otherwise, my advice is -- don't bother, assuming that you can replace the UPS battery even when it is mounted directly into the server rack.

I have not experienced any particular benefits from having the rails. It could mean a lot of time wasted trying to get them adjusted correctly. This is especially true if you are doing it yourself, have not done it before, or are just not confident. In these scenarios, just install it in place without the adjustable rails.

3. Prepare for installation

A very important point to bear in mind is that you should never attempt to install a UPS by yourself, unless you are handling a simple, small UPS. The weight of most UPSs is substantial.

Even if you can carry your eight-year-old on your shoulder just fine, you must remember that the weight of a UPS is condensed into a relatively small package with an extremely poor weight distribution -- the dense battery is normally located in one end, and it has hard metal edges on most sides to boot.

In addition, keep in mind that you are dealing with electrical equipment, and there is always the chance of an accident. While you might like the peace and quiet of installing it over a weekend or late at night, to be safe, make sure there is someone else around.

Have you been in charge of acquiring and installing UPS before? What are your experiences with it?

About

Paul Mah is a writer and blogger who lives in Singapore, where he has worked for a number of years in various capacities within the IT industry. Paul enjoys tinkering with tech gadgets, smartphones, and networking devices.

23 comments
sameer_a_gaikwad
sameer_a_gaikwad

UPS selection for large installation consists of evaluation of following parameters - 1. Battery type and size (12v or 2V Vrl ) 2. Battery derating factor ( depends on temp and expected charge discharge cycles ) if it high one can save money by using less capacity batteries 3.Conversion technology ( thyristor or IGBT - single or double stage) - decides power quality and harmonics 4. Redundancy - hardware and software 5. Parallel operation 6. single or three phase input 7.Input power factor and efficiency 8.Load and line regulation 9.harmonic distortion 10. Remote diagnosis

renu
renu

can you please mention how much power appoxly A WS takes, A server takes....such a breakup????

DPeek
DPeek

I used to work for a storage vendor before relocating to Japan. At the time it was all FC all day. Here is a pretty simple tip that not all customers understood. If you place your storage and server on UPS, make very certain that in the event of a shutdown scenario, that the server goes down (safely) first. Your storage is seen to the server as a big hard drive. Quite often that storage (If its a SAN or even just most regular production storage)is being accessed by users and or processes. If the storage powers down safely while being written to or read from, it WONT be as pleasant as if the SERVER and its processes safely power down first. Seems simple, but some customers were adamant about UPS protection for their storage with no thought given to what would happen during actual usage (beyond the pretty blinking lights).

S,David
S,David

It has been my experience that before buying a UPS that one should first learn what Power Factor and kVA mean. Next, that if you plan to load a UPS at more than fifty percent of maximum, you need to consider a bigger UPS, both for the extra headroom for new equipment, and because sucking full power out of batteries heats them up, reducing their life. If you ever plan to add a generator, the UPS you buy should have adjustable thresholds for voltage, frequency, etc. on the high and low side, and be able to correct these on the output side. Finally, if you are going to get a hardwired UPS, your electrician should know about computer power systems. Not all of them do enough of that kind of work to keep it fresh in their minds.

57ford
57ford

Batteries don't last forever, although the rest of the UPS probably will (I'm pretty sure I have one APC that is 20 years old now). If you have "smart" UPSes, they'll do their own periodic tests under load. If they're small dumb UPSes, check them monthly. Undersized batteries tend to die more prematurely (like the ones in certain 250VA and 500VA models from APC). You can generally buy equivalent replacement batteries cheaper from local electronic parts dealers. If you don't have some kind of asset tag system, put some ID numbers on the units so you can keep a file of where the units are deployed, when they were purchased or put into service, and when the batteries have been replaced. If the UPS has an interface port, you might as well take advantage of it. In the event of a long outage the computer can shut itself down properly, and shut off the UPS as well. Allowing the UPS to continue running off the battery until it is flat will shorten the lifespan of the battery. Also, logging the UPS events may be of some value.

dibthree
dibthree

It surprises me that in an article about selecting a UPS there was no mention of making sure it is Double-Conversion for servers and important hardware.

paulmah
paulmah

Have you been in charge of acquiring and installing UPS before? What are your experiences with it?

Color me Gone
Color me Gone

One piece of test eqpt not mentioned it a Power indicator. The ones I've seen online look like a small power strip. All you do is plug it into the wall, plug the eqpt in and get a wattage reading. No more guess work. I recently purchased a Cyber Power 390 watt 685AVR unit for home use. Their barely adequate software indicates that I have 12 min runtime with 206 watts used. The box indicates that with a 17" LCD (I have a 19) I should get 45 min. Big difference. Another thing to consider is trying to have outlets in server rooms on different fuses.

paulmah
paulmah

Yes, you are right. I'm working on a follow-up on typical installation issues and I'll be sure to mention that.

ups power supply
ups power supply

I put the installation of an ups as following for your reference: Power fluctuations and sudden loss of power are issues that can both result in serious damage to computers and their peripheral devices. An uninterruptable power supply, commonly abbreviated UPS, is a device that is designed to maintain a steady and constant source of electricity to your devices. A UPS takes the power supplied from an outlet and stabilizes it before feeding electricity to the devices connected to the included outlets. In the event of a loss of power, the UPS switches from main power to a battery backup, which gives a user the chance to save any data and properly shut down the devices connected to it. Step 1 Set the UPS device on a solid, level and dry surface close to both a power source and your computer equipment. To avoid overheating, place the UPS in a location where it can get adequate airflow. Step 2 Plug the UPS into a wall outlet and then connect all of your devices to the available outlets. Step 3 Press and hold the power button on the UPS for about two seconds. This will initiate a self-test procedure. Once the self-test is complete, your UPS will be ready to supply steady power to your devices. The internal battery will charge while your devices are in use. Hope this will help you.

Ethical_Loner
Ethical_Loner

If you are willing to accept the professionals' opinions and recommendations APC's web site has a calculation process you can use to determine what UPS to purchase based on such factors as load, length of time you want to sustain systems in the event power stays out, etc. It even offers drop down lists of major server makers' equipment (as well as other non-server equipment) with the information already taken into account to make it really easy. It's a free service and I would suggest this as a first step regardless of whether or not you purchase from APC.

knudson
knudson

First as mentioned, most have fully(battery) and partial(surge) protected outlets. Then some discussion should have been about the differences between (in APC terms) Back UPS and full(?). One provides power via the batteries 100% of the time, one switches when needed. Note though most PC power supplies can handle that switch time easily. Finally APC (my fav) has put out several warnings that over testing, ie cycling the UPS, degrades it's lifespan. So don't run a full check that often, 2 or 3 times a year s/b sufficient.

erbngeek
erbngeek

I was doing a server spec/install for a customer and through my investigation found that higher voltage circuits and servers are more power efficient with less heat. Not knowing about 3-phase circuits, I just figured 208v/220v was the same (like sometimes 120v/125v is listed in specs). Little did I know how wrong I was. I ordered 2 208v UPSs, and had 240v circuits installed. I didn't realize my mistake until the UPSs would not turn on. I called tech support and found out that I had 208v UPS which is what the servers required, but had them plugged into 240v lines. The customer did not have 3-phase circuits, nor was replacement very cost-effective. Once we set the tolerance on the UPSs to higher values they did turn on and I was able to use them. So my options were 1)install a 3-phase (thus 208v) circuit into the building 2)replace the UPSs with different ones or 3) keep things as they are. The first 2 options were cost prohibitive. In the end, APC stated they still warranty the UPSs, but that life expectancy will be shorter for units that are constantly running on overvoltage circuits with AVR Trim active. In any case, they have been running for a year-and-a-half with AVR Trim reducing the voltage to ~208V for the servers. I will make sure I get a 240V input UPS model that has 208v output when they need replacement. Side note: Network Remote access modules for UPSs are great for those times that you need to hard power cycle a system but are not on-site, nor have anyone to do so.

mjd420nova
mjd420nova

I really like the Tripplite units, they are efficent and easy to use with very good instruction manuals that cover all the neccesary things a user needs to know to properly implement their correct usage. I also like their ease of replacement of the batteries when they go bad. There are many units out there and all will do the job if the users will just read the manual and look at the plug in outlets to be sure they get connected properly. One thing that users should note is that only essential equipment should get plugged into them, no printers or external devices and only those essential units such as backup workstations and servers. Only the most essential units and their monitors should be connected, as the monitors will suck up the power faster than most desktops.

robo_dev
robo_dev

the top row says "Battery Backup / Surge supression" and the bottom row says "Surge suppression". These are printed in gray on a dark gray case. After the UPS test failed (since I had plugged into the surge-only side), I actually had the unit partly disassembled on the workbench before I noted the labeling on the device and subsequently read the manual.

boxfiddler
boxfiddler

You're dredging up zombies. UPS zombies, at that. :|

S,David
S,David

Yeah, I just barely dodged this, too. What causes the confusion is that some large systems will show they are a 208v system when they will take anything from 208v to 240v, single phase. And, 208v, even though it is obtained from two phases of three phase power, is single phase. We had an IBM system like that. Their configurator showed it as a 208v system, and as we do have some buildings with three-phase power, I thought they had made a mistake. But, they said it was just the way their systems were documented and that the power supplies would auto-range between 208v and 240v just fine.

jrosewicz
jrosewicz

I've seen this happen many times where the person who installed the UPS didn't notice the designation of Battery vs Surge on each side. The other mistake I've seen is people forgetting to connect the battery before deploying. My biggest issue is dealing with Batteries. The batteries have a limited lifespan and replacing them can be a hassle. With APC brands I have trouble figuring out which size I need and it almost ends up easier to buy a new UPS. With most low end battery backups you really don't know when the battery is bad until its too late. I've been looking into Tripplite UPS systems. They are very friendly and their website will even calculate your power needs and suggest the type of UPS.

paulmah
paulmah

Good thing you did a test and discovered that. Would be ironic to not realize it -- not that hard to do if you're installing multiple UPS at a go, and have all the servers crash the moment there is a power outage. Regards, Paul Mah.

Dr Dij
Dr Dij

one workstation I asked for mini-UPS for, later noticed the pc dept had put it in without connecting the battery. Not all are sold like that but this one required it. if you're interested in data center sized UPSes there are about 3 courses in sizing UPSes and when to use the huge wet cell batteries, when to use modular ones.. and difs in types and power efficiencies. it is at datacenteruniversity.com, and they are free currently. the sign says they will soon start charging $80/course. I went thru all 50 of them for free (other courses are unrelated to UPSes except for power supply and distrib, other courses are on racks, cooling, estimating..). they are reasonably vendor neutral, even tho APC set them up on the global knowledge platform and sponsors them. there are a few mistakes in the courses and questions which APC never responded to my emails about but this didn't detract significantly from the value of them.

ddouglas
ddouglas

I have used and recommended Tripplite as an UPS solution. Their products have come a long way and are compatible. APC also offers calculators on their website. One interesting thing about APC is that they are currently offering trade-ins for certain units which helped a recent client of ours. Since they are a non-profit, they had real cost concerns and with the trade-in program that allowed the organization to get rid of the units instead of finding or paying to have them disposed of properly.