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I have two server, with redundant PSU's connected to two UPSs.

The UPSs are APC Smart-UPS 1500VA and I want to shut down the servers when the power gets low. However, because I have a redundant PSU then it becomes a bit difficult to manage.

How am I supposed to be able to shut down the servers when I am drawing power from two batteries?

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Which behaviour is expected ... running as long as ONE battery can still supply any power, or playing it safe? Also, do you want to deal with the scenario of one upstream supply to an UPS failing, or are they fed off the same fuse anyway? Are the redundant PSUs active/active and EQUALLY loading their input (do not assume they are, killawatt them!)? – rackandboneman Jul 19 '12 at 11:30
I'd like to keep running as long as possible. Both PSUs draw from the same circut but they are generator backed. I have no idea about the redundant PSUs unfortunately. I know they are Fujitsi Primergy RX200 S6 s but the spec just says 2x Hot swappable PSUs. Nothing about their power state. Ill try checking their manuals to see if I can find anything there – VBwhatnow Jul 19 '12 at 11:44
The manual suggests the PSUs are active/active. "System performance will be throttled to max. 450W until the defect PSU is exchanged" – VBwhatnow Jul 19 '12 at 11:59

The built-in power management functionality in Windows Server 2008 will detect both UPS devices and show that the server has two batteries installed. Here's a screenshot from a Windows Server 2008 machine with two APC 1000VA UPS devices attached via USB:

Windows Server 2008 battery screenshot

Once you've got both UPS devices connected you can set low / critical power thresholds and actions.

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