How do you set-up your UPS`s on servers with redundant PSUs?????

[burgemaster]

All our 8 servers now have redundant power supplies. We have 3 x large rack mount UPS`s in-case of a power outage.
Im a little confused to the best set-up, should BOTH PSU on the one server go to the same UPS or maybe a different UPS?
This will make it difficult setting a shut down during a powercut as levels drop because different UPSs will have different loads and thus drain quicker/slower than the other 2?

What is the suggested setup with dual PSU and APS units please?
Thanks in advance

[Steve21]

I don't know the official way, but surely having it plugged into the same UPS is just another point of failure? One UPS goes down, and you lose the server.

Steve

[synaesthesia]

Easy one - one direct into mains, one direct into UPS. UPS fails, you're still running (although UPS are supposed to then act as a direct passthrough but it's best not to take the risk). Power fails, UPS kicks in.

[Heebeejeebee]

Al ours are one in the mains and one in the UPS.

HBJB

[sidewinder]

I plug one into one UPS and the other into another UPS (only have one of them performing a shutdown though)

[DrCheese]

We have one in one UPS and one in another.

Make sure tho that your UPS's can take the load if one fails. i.e if one UPS dies the servers will draw more juice from the other remaining UPS. If you don't test in advance that your UPS can handle that, it may overload it and kill it anyway, defeating the point :P

[burgemaster]

Looks like we need some more mains sockets put in the server room then!
Thanks for this.

How would you go about allocating the 3x UPS? i take it you cant daisy chain them?
Just share out the servers between them?

[pete]

Looks like we need some more mains sockets put in the server room then!
Thanks for this.

How would you go about allocating the 3x UPS? i take it you cant daisy chain them?

Don't daisy-chain them.

Just share out the servers between them?

Balance the power draw across the UPS' so they're as even as you can make it. Bias load towards the newer UPS' if you can't make it quite even.

[AngryTechnician]

I have each power supply plugged into a different UPS. I used to have one in the mains and one in the a UPS, but then you are bypassing the mains surge protection that the UPS provides.

All of ours in the server room have Network Management Cards installed, and APC provides software for these which means each server can monitor both UPS feeds individually and make shutdown decisions accordingly, e.g. only shut down if both batteries are low, rather than if it's just one of them.

Load testing is certainly important, but in practice is quite difficult to do as people get upset if you test in school time and it goes wrong! Fortunately (or unfortunately) we had a half-day site-wide power outage last year which gave me an impromptu live test without anyone getting upset if it failed (since all the client workstations were off anyway).

[burgemaster]

Thanks,

We have 3 x "APC Smart-UPS 3000RMi 2U", each has a management card but only one has the card with the environmental sensors. Ive not seen a way to monitor other UPSs? are yours made by APC?
After an air-con failure i wanted all servers to shutdown on high temp, but was told that I needed these upgraded cards in each of the UPSs.. I will have a play with a script to launch that could shutdown them all...

[AngryTechnician]

Ours are APC. The software we use on the servers is PowerChute Network Shutdown 3, and when you configure it (on the server, not on the NMC web interface) you get a screen like this:

pcns.png
(click to zoom)

When you pick an option that uses more than 1 UPS, you get multiple boxes on the next screen to fill in with IP addresses of each NMC.

The problem if you wanted everything to shut down based on the temp sensor is that you would have to set every server up to monitor that UPS. While this is perfectly possible, it would mean they would also receive and act on low power events from that UPS even if they weren't plugged into it.

[burgemaster]

We are using "PowerChute Network Shutdown 2.2.4"

Looks completely different! thanks I will look into that now