Comment by dragontamer | Hacker News Reader

Comment by dragontamer | Hacker News Reader

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> While I was away from home on a long work trip, suddenly I could no longer connect to my server and I had not received an e-mail from the server informing me of any problem. Luckily it was near the end of my trip so I was not too inconvenienced. When I arrived home I found that the UPS was sounding an alarm and was not supplying power to the server even though there was mains supply to the UPS. 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.e. there had not been a power cut while I was away. Fortunately there was no loss of data on the server; I was able to run fsck during boot-up.

And this is why professional servers have two, redundant, power supplies.

If you had two power supplies, the UPS would fail, but you'd continue to function off of mains voltage.

UPS can fail. Mains can fail. Two power supplies hooked up two both powering your server redundantly means you'll only fail if both fail simultaneously.

That's not really a proper way to deal with it. Proper UPS for a home server or any standalone server or appliance has to hook up either after ATX power supply in parallel and provide all the ATX voltages or hook up directly into a power supply to save a bit on extra converters. This way UPS failure won't affect anything and such UPS will be much more efficient.

It's just that consumer home UPSes are almost scam level products designed to profit from naive people. They are both not improving things for an average user and killing batteries after like a year of operation (lead acid batteries can last for like a decade when not subjected to those UPS chargers).

My cheapo UPS certainly improved things for me when I lived in an apartment where the entire unit minus kitchen appliances was wired to a single 15A circuit. I tripped the breaker semi-regularly by forgetting to turn off the AC before using the vacuum cleaner or toaster oven or whatever.

That doesn't protect against surges though - any weirdness from the mains power would still fry your server through the unprotected power supply.

Surge protectors are pretty cheap, and I generally assume that all expensive equipment would use them when connecting to mains.

Also, surge protectors wear out and should be replaced before they lose the ability to protect.

This will probably occur at a different time than when the UPS wears out, so it could be beneficial to keep them separate so you can replace the surge protector only.

You don't need an UPS to protect against surges. In fact, UPSs aren't surge protection devices; they may filter a few of those, but they should be protected too.

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