Help me diagnose what happened with my UPS +unRAID

Skilid · 28 Aug 2022 at 13:29

I have an unraid server connected to a Cyberpower UPS, which is designed to gracefully shutdown when the UPS gets to 40% battery capacity or less, or 20 minutes of run time or less. The other morning I awoke early in the morning to the sound of my UPS beeping. I thought to myself that there must be a power cut and I didn't need to worry as the UPS will handle it. 10 minutes later it stopped beeping and I got up, thinking that the power must have come back on, except it hadn't. I went downstairs and found that my my main RCD was tripped, so it wasn't a power outage. Went back upstairs to find my unRAID server was off and the battery on the UPS was fully charged. After turning the sever back on, it told me that it did not do a graceful shutdown, but an unexpected shutdown (as if you'd pulled the power cord) and didn't have a UPS.

1. Wasn't a power cut as the RCD was tripped.
2. The UPS was fully charged, even though there was no power, so it obviously hadn't been powering my unRAID server.
3. The UPS was beeping to suggest that the power was out, but it stopped beeping before I switched the RCD back on. It usually only stops beeping once power is restored.
4. Once everything was back up and running I tested the UPS by switching it off at the wall. It started beeping as usual and powered my server until a graceful shutdown, as it should. It has worked several times for me in the past, also.

What the hell happened? What could have caused the RCD to trip? Why didn't my UPS power my server? I can't get my head around it. The UPS and unRAID server are both less than a year old.

Thanks.

BongoHunter · 29 Aug 2022 at 17:55

The only way your going to diagnose this is to test it, maybe there was a brief outage, the UPS went to battery and then when power was returned the UPS tripped the RCD?

Testing your server against the UPS should be easy, pull the power cord out the back and see what the server does.

Testing the UPS against the mains should be easy as well, flick the trip with the UPS on it and see what happens, when you reintroduce supply does the UPS cause the RCD to trip?

How old are the batteries in the UPS out of interest? Have you ever cycled them - how does it compare now to when you last did it?

Skilid · 30 Aug 2022 at 09:32

BongoHunter said:
The only way your going to diagnose this is to test it, maybe there was a brief outage, the UPS went to battery and then when power was returned the UPS tripped the RCD?

Testing your server against the UPS should be easy, pull the power cord out the back and see what the server does.

Testing the UPS against the mains should be easy as well, flick the trip with the UPS on it and see what happens, when you reintroduce supply does the UPS cause the RCD to trip?

How old are the batteries in the UPS out of interest? Have you ever cycled them - how does it compare now to when you last did it?

Thanks for your reply.

Regarding your first point, if there was a brief outage and UPS went to battery, the server shouldn't have turned off. It should have kept running until the UPS battery got down to 40%.

Regarding testing, I've performed both of those actions several times since and all is working as it should. Battery kicks in, server stays on, no RCD tripping.

UPS is only a few months old. It was a replacement for another that was DOA. Never had any issues with it before.

Silicon Si · 30 Aug 2022 at 10:54

One of the batteries may be duff I had that on a ups that used to die on a fortnightly self test

Skilid · 30 Aug 2022 at 12:55

Silicon Si said:
One of the batteries may be duff I had that on a ups that used to die on a fortnightly self test

Pretty sure there is only one battery. Subsequent tests have all passed.

Bluecube · 30 Aug 2022 at 13:17

I’m only asking this so we can dismiss the obvious - the server is connected to the UPS? And the UPS shows up in Unraid via the USB connection?

Skilid · 30 Aug 2022 at 16:18

Bluecube said:
I’m only asking this so we can dismiss the obvious - the server is connected to the UPS? And the UPS shows up in Unraid via the USB connection?

Yes and yes. It's worked flawlessly in the past and works flawlessly now if I test it. Just this one occurance I cannot work out what happened. Only thing I can think of is the UPS did something weird internally. Maybe a random energy spike or something? That could have tripped the server PSU (protection) as well as tripped my RCD. I'm not sure what it could have done to cause this, though.

Armageus · 30 Aug 2022 at 16:23

Which model/capacity of UPS?

What sort of hardware is in you server (in terms of load)? Make/Model of PSU?

Skilid · 30 Aug 2022 at 16:35

Armageus said:
Which model/capacity of UPS?

What sort of hardware is in you server (in terms of load)? Make/Model of PSU?

UPS is a Cyberpower VP1600. It is capable of delivering 960watts.

My unRAID server is very basic:

11th gen Pentium Gold with 3 HDDs and a cache sata SSD. It doesn't draw over 15-20 watts at idle as the drives are not spinning after 1 hour of downtime. Has a Fractal Design 550w Ion Gold PSU.

I also have my desktop PC and monitor connected to the UPS, but the desktop was off and the monitor on standby.