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    the next time I have to buy a UPS for a piece of equipment that requires power 24/7, I will buy a line-interactive UPS rather than a standby UPS

    I’ve been wondering why one would get an office, standby UPS for a server (home or otherwise), but then I realized someone who has never been designing server installations indeed has no way to even know what keywords to look for.

    And now that fewer and fewer companies even have on-premises server rooms, it may be becoming a somewhat obscure knowledge even among professional sysadmins.

    Maybe it’s time for a collaborative “how to make a server closet” manual…

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      I would certainly welcome a guide like that.

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        I second this. It would be extremely valuable to some of us who are less familiar with this.

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        That would be a lovely piece for all of us with nascent home datacenters. :-)

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          “how to make a server closet” manual

          Time to dig through the photos I still have for “how not to make a network/server closet!”

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            I’ve just started playing around with some home server gear, and the best general resource I’ve found is the r/homelab wiki. The Hardware Guide was particularly useful to orient myself to the world of decade-old enterprise servers, but it’s UPS subsection doesn’t mention this “line-active” terminology.

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              Maybe it’s time for a collaborative “how to make a server closet” manual…

              That would be awesome.

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                how to make a server closet


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                Buying a cheap UPS is usually a worse idea than having no UPS.

                A lifetime ago, I worked in an office where everyone had their workstation on its own APC UPS instead of a regular 6-port power strip. I believe this idea came about because most of the floor was for helpdesk personnel and hanging up on your users is not considered good customers service. However, the building also had a huge battery backup system and diesel generators out back meaning the power basically never went out unless there was planned maintenance. However, those little under-the-desk UPSes died and malfunctioned constantly. Mine would just turn everything off for no actual reason that I could tell. No problems with the battery, no alarms, nothing. Just unplug it, plug it back in, and it was hunkey-dorey for another few weeks.

                I eventually swapped mine out for a regular power strip.

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                  Realizing UPSs generally suck, particularly the well-marketed ones like APC’s back-ups line, is the natural consequence of buying one such UPS.

                  ESR did come up with a project to disrupt the UPS market, but unfortunately it’s not quite there yet, years after the fact.

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                    I read this and missed the author stating the following prior to the failure:

                    • That a monthly UPS test to validate the UPS was in good condition was done prior to the failure

                    A UPS isn’t infallible, just like a backup plan (really a restore plan), or unit testing, you have to exercise it to know if it will or still works. You do this when you’re beside the system, not when you’re away. If the battery is dead its better to find out when you’re able to fix the problem than later. Exercising the battery will also help keep it alive longer.

                    I have had a much simpler ups than what this guy bought and did a monthly (recurring sunday task) test. I then timed the discharge by the time it got to its listed “about to die” spiel on the front panel and plugged it back in. Well I didn’t plug anything in, I actually have a wireless remote attached to a mains adapter that lets me turn power on/off with a button. (Yes I am that lazy and would prefer not to unplug mains cables that much). My battery/ups lasted a good 4-5 years and all I did was a monthly make the battery do its job test. Once the battery lifetime was about 50% I knew it was about time to call the current battery done.

                    Test your stuff! Don’t assume its fine, it isn’t, make it demonstrate it will do what you want it to.

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                      If anyone is looking for a decent UPS for home use, I can highly recommend the CyberPower CP1500PFCLCD. I have two, one powering my networking equipment and a small server, and another powering my workstation. I’ve had a handful of outages, and they worked wonderfully. I checked after reading this article, and this model is line-interactive.

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                        How long have you had them? Have you observed any degradation during that time?

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                          I’m only coming up on a year, but I haven’t noticed any major degradation going by the estimated run time that the unit reports.

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                        “It transpired that the UPS battery had suddenly died without warning and could no longer hold a charge, and this had happened while there was mains supply to the UPS”

                        I once brainstormed that the better alternative to a lead acid battery UPS would be something that:

                        • Had a set of ultracapacitors, just enough so a home server UPS can safely power down.
                        • A way to trigger over IPMI to make it go back on once the power was back on reliably. There’s some very high end UPSes that utilize ultracaps and some engineering prototypes from a few years ago, perhaps its just been too niche (along with ultracaps themselves being high in price) to sell as a consumer product.
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                          I had a UPS on my desktop for a while because 5 second power outages were pretty common. I noticed the thing used to run really hot. It must be wasting a huge amount of power while not actually providing any value most of the time.