APC UPS - Best Practice - configuring events and shutdown

The point of having 2 power supplies in a server is to imagine that one will fail and the other will keep going. Accordningly, you want both power supplies connected to UPS units.

Why? The very instant the power goes out, the power supply on the UPS will fail and the power supply connected to the wall will be OK (but the power is out). Murphy's Law is incredibily real.

One the second question, a medium to small UPS will want to shut down the computers after about 6 minutes in a power outage to provide time for an orderly shutdown ( which itself may take several minutes). You need to look at the UPS specifications and the default parameters it has. If you wish to change them, you should test with a simulated outage. Power outage is the main parameter to consider.

... Thinkpads_User

I concur.. each power supply in the servers should be connected to a different power source. What we do is have multiple UPS devices on different electrical Circuits, then have each power supply in the servers connected to the different UPS'. the problem you have at the moment is if you connect 1 to the UPS and 1 to the wall, is what happens if there is a surge or a stop start event that causes the power supply to blow up ? is it going to take the servers motherboard / hard discs etc with it.. you can guarantee it wont.. you 'really' need another UPS for this to be fully redundant..

Hi experts;

thanks for the quick reply; very interesting point by psychofelix.

We do have 2 UPS; however they are different model; is this still work?
Also we have 1 power goes to UPS 1 and the other goes to UPS 2; does it mean we have the same clients for both UPS on the PCNS management card where we define the IP addresses for all clients?

also if one of the UPS is failing; the server will still run from the different power source; will the management card still sending the "shutdown" command to the server?

sorry; a lot of questions here; still very new with UPS world

please advise

sorry: i meant
"IF we have 1 power goes to UPS 1 and the other goes to UPS 2; does it mean we have the same clients for both UPS on the PCNS management card where we define the IP addresses for all clients?"

the 'clients' I assume you mean the APC software ? you'd set the two management agents with different IP addresses otherwise you wont be able to access them..

In terms of which one to send the shut down commands, personally I'd only configure the UPS with the largest capacity to issue any commands, that way you're ensured that you'll get the longest run time and the power 'may' come back on before it has to shut it down anyway..

dont have anything setup on the smaller UPS.. use it just as power conditioner and limited backup in case the primary power supply dies etc..

hi there,

how do you setup 2 management agents in 1 server? is there an option to setup 2 management IP address? I can't find it anywhere to setup 2 management IP addresses under PCNS. can you please help?

what happen if the primary ups goes down? is that mean the server won't have a graceful shutdown?

please advise

hi there,

just want to confirmed that we don't really have to do anything on the lower power PSU (ie: defining the IP addresses of clients in the management IP of UPS), etc; just simply plug the 2nd PSU from the server directly to the UPS?

cheers

thanks very much for your help