The power went out at the office yesterday. I’m telecommuting today, but I can’t connect to my computer because someone needs to turn it on. It’s a bit of a pain, since I like to start at 6:15 and the office isn’t populated until 8:00 or later. So I thought I might buy a backup power supply. A very brief look says a 600A power supply will last about 20 minutes under a 100W draw. I don’t know how long the power is usually out. Of course, the computer isn’t being used when the power goes out. How long will a backup power supply last with just the computer on (in sleep mode) and the two monitors in sleep mode? Any idea what the draw on a sleeping computer is?
I do not know the answer to your question of using a UPS to keep your PC running.
What I would recommend instead is looking into Wake-on-LAN. There should be a setting in the BIOS/UEFI to allow WoL after a power outage (of course, this may vary by machine).
There is not strictly speaking a single answer. You have to actually find out the draw of your computer (which varies considerably based on what hardware we’re talking about) and then the capacity of the UPS. In typical practice the standard-ish sized UPSes and the standard-ish build outs of business desktops, you usually are talking a matter of minutes not hours, their main purpose is to give you time to save your work and etc and gracefully shut down if the power is going to be off for an extended period, and additionally to keep you going during brief interruptions in power.
There are scenarios where a UPS can keep a PC going for hours, but such a UPS will be more expensive and much larger physically so they aren’t that common at the desktop level in an office.
It’s worth noting that unless your whole office has some power redundancy, if you are remoting into a desktop at a work desk, it having a UPS to keep the desktop going only does so much–mainly it will prevent your PC from shutting off completely from lack of power, so if the power comes back up you’ll be able to reconnect. But unless all the networking hardware etc in the office has power redundancy you will lose your connection for the duration of the outage.
We do not have power redundancy in the office. You’re correct that I’m dead in the water if the server goes down. But the server comes back up when power is restored. The computers do not.
My office computer is a Dell OptiPlex 3050. I’m having trouble finding its power draw. Googling, one answer says the OptiPlex 9020 draws 10.2 watts. The Dell owner’s manual website says the power supply is 65 W. And the input current is 1.7 A / 1.0 A. Another site says the PSU is 180 W.
ETA: The ‘early bird’ coworker started my computer for me this morning.
Oops. I didn’t see your reply. I’ll ask IT about it.
Even better: look for a “power state” (sometimes called “AC recovery”, “restore on power loss”, etc.) option in the BIOS and set to “power on” or “last state”. If the outside power is cut, then the PC will boot up again when the power is restored.
I looked up the OptiPlex 3050 manual and the setting you want is in the BIOS under the Power Management section, called AC Recovery. Set to Power On if you want the computer to always come on when the power is restored, or Last Power State if you only want it to come back when it was on in the first place.
It depends on your specific configuration. The micro has a power supply rated at 65 W. The small form factor is rated at 180 W. And the tower is rated at 240 W.
https://www.dell.com/support/home/en-us/product-support/product/optiplex-3050-desktop/docs
Or as a rule of thumb, unless you grossly overbuild your UPS - it’s usually good for something between 20 minutes and an hour - i.e. long enough to survive most power outages and bumps nowadays, but not a serious one. Nothing more annoying than the light flicker and your computer reboots, and a half hour of work is lost.
Yeah, UPS devices are usually designed to permit graceful shutdown in the case of power loss, and power smoothing for very brief/momentary interruptions as a secondary function. If the power is going off for multiple minutes at a time, routinely, UPS is probably not the perfect solution.
The funny thing about graceful shutdown is that it can be harder to “recover” from in a remote environment. I’ve run into this on Windows Server and other systems where the UPS is connected to the computer with the USB communication cable, and the computer is set to shut down after the UPS gets close to running out of power. That’s definitely a graceful shutdown, but it also sets the “last power state” to OFF so the computer will not restart on its own when main power is restored without some sort of hack or lights-out management hardware. The “solution” was simply not to use the USB connection and let the UPS cut off the power when it ran out of juice. Not ideal for sure, but better than requiring physical presence to restart the system.
this tended to be the best solution when typically power interruptions are fairly short. I guess it depends on the locale. I know most power outages in my home are usually resolved within a few minutes. I presume the electric company has remote control of assorted breakers etc. in the distribution system and often these are still remote-controllable even when tripped.
More likely autoreclosers. They cut off the power when a short is detected, but they then reconnect and disconnect a couple of times, sometimes with a big surge of power on the last try. The idea is to burn away the tree branch or balloon or unlucky squirrel that caused the short if it didn’t fall away from the line on its own. A UPS is great for riding out stuff like this, assuming the fault is cleared before the recloser gives up and shuts down the circuit completely.
A friend of mine relates the story where a relative was moose hunting up north. The guy climbed a high voltage tower to look for moose, assuming if he did not touch the wire he was safe. Instead, he got close enough (couple of feet?) to get a massive shock which apparently tripped the line off too. His buddy went up to retrieve him and got him to hospital. The hydro company reported they were lucky. The line was having some sort of work done, so they had turned off the automatic reclosure of the line, otherwise they would have both been zapped. (Repeatedly?)
Been there - even in an onsite environment it could be a PITA - the UPS client/driver had a threshold for when a momentary fluctuation/loss of power should be considered an outage, and honestly, it’s best to set this fairly short - like less than 30 seconds, except that then you get the situation where everyone says ‘oh, it’s OK, it came back’ - except in IT, we know that the servers are now in their shutdown cycle. - a 29 second power outage is 29 seconds downtime. A 31 second power outage is about 15 minutes downtime.
Update: I’ve just received an email from IT:
Someone at [IT support company] could send a wake on LAN command from the server, but it would likely take longer for someone at [IT support company] to get to it than someone on site at [office]. And it would likely cost more.
So I’ll just have to continue relying on the kindness of a coworker who is in the office when this happens.
Many computer have a power-on alarm setting in the BIOS. You can set it to always turn on at 7am, or whatever. If the computer is on, nothing will happen. If it is off it will turn on. I use that setting, combined with a UPS, to get hands-off recovery on an old Dell Optiplex desktop repurposed as a home server.
Brief power outage:
UPS provides power; computer stays on
Long power outage:
UPS reaches low power; shuts down computer; UPS dies; AC recovery (set to on) brings it back when power returns
Just the wrong length outage (of course the one experienced when not home):
UPS reaches low power; shuts down computer; with no load on it UPS runs for a while longer and wall power returns; UPS never turned off, so AC recovery does not turn computer back on, because as far as the computer knows, the power was never off; alarm timer turns computer on at designated time