Best practice for UPS wiring?

[talksr]

Hi there,

I have two racks with 9 48 port switches, one router and one firewall and currently

Three x Dual PSU HP Servers

Two x Single PSU HP Server

 

We have two rack mounted APC 1500 UPS units which have three 'groups' on each UPS. Groups one and two have two plugs per group and group 3 has four.

Here is a picture of the back of one of the units.

 

My main question is... would there be any benefit in wiring the dual PSU servers to both UPS boxes? So that if the power were to fail and one UPS also failed, the second would keep these larger servers running?

My only concern is how the server would know to turn off as it wouldn't know which UPS to listen to?

 

 

 

Alternatively, does anyone know if these UPSs are able to be linked together to form one unit so to speak? I have tried joining the Serial Leads of each UPS together with an ethernet lead, but it has not helped. Can't find anything in the manual re this.

[round2it]

have a monitor on the ups, just in case you want to manually shut them down,(voice of experience here) not good when you have to wire a monitor in as the power is draining.

[NB9457]

We use two UPSs, both slightly different, each server is connected to a separate UPS, this helps prevent damage from power surges, adds redundancy should one of the UPS fail.

 

With regards to the knowing when to shutdown, it's over network, so the servers will be told to shut down by the UPS with the NIC in as its batteries start to drain, but most servers load balance PSUs too, they're not just for redundancy, so if the UPS are both the same or similar, the battery drain should be similar, should the standalone's battery go first, the load will be passed over to the other PSU linked to the other UPS.

 

Hope that makes sense.

[talksr]

Thanks both, good idea about the monitor too, though I would need a KVM ideally as would be a nightmare switching VGA cables between the different appliances.

 

This was the approach I was thinking of going for as per the APC guide. It is called Redundant in their terminology...

 

These are some of their other options...

Parallel-UPS Configuration:

 

Advanced:

There is also Single, though that speaks for its self.

 

My only concern with these setups is the obvious... if the power goes down, unless all network switches are powered on via the UPS also, what is the point of the shutdown commands going out of the UPS devices, as the network is down, so the servers will not receive this communication.

 

My UPS devices are on my management vLan, which would mean I can either receive the shutdown signal via our curriculum, admin or management vLans (Admin and Curric are able to communicate with management). So I may need to look at adding an additional NIC to each server and then ensuring that a switch is connected to the UPS that has all management connections on it.