K460 - UPS needed?

[Tim Krego_1]

We have a K460/AutoRAID machine that has an HP Powertrust UPS connected to it.

My question. The machine is in a data center that has a generator.

Is there a reason to keep the HP UPS connected?

If the datacenter also had a UPS would we still benefit from having the HP UPS?

I know the UPS can signal the K460 to shutdown. But if the datacenter has UPS and generator capabilities we could save rack space my removing the UPS.

Thanks.

[A. Clay Stephenson · Accepted solution]

If the data center has a generator but no central UPS then you absolutely need the HP UPS
because the generator will typically not start and accept load for about 5 seconds minimum and typically 30 seconds to 1 minute.

If the data center has a central UPS to cover the generator startup period then, in general, the answer is that you do not want to connect
another UPS in series. Many UPS's 'buck - destructive ferromagnetic resonance' when
connected to another UPS.

I assume that this is a Model 12H AutoRAID - you should bear in mind that 2 of the 3 power supplies must be available.

[Yogeeraj_1]

Hi

Don't forget that there will be a slight delay between a power-cut and the generator taking over - enough to power-off your server (what about spikes, glitches and other types of fluctuations in power?).

The UPS can also be used to send a signal to server for shutdowns as you already know. There are also UPS monitoring software that run over the network.

Hope this helps!

Best Regards
Yogeeraj

[Tim Krego_1]

What kind of software signals power outage over the network. Is this something that uses SNMP?

Is it HP specific or will it work in a mixed Windows/Unix envrionment?

Is it vendor specific also? Say APC or another vendor.

I'll see if I can dig up more info on the web.

Thanks.

[A. Clay Stephenson]

Tim:

In a very real sense if you have a UPS and a generator there is really no need for a powerfail shutdown. It's just not gonna happen.