How to correctly calculate kW (kVA) for all servers?

Question

Iron

There are several dozen servers.
We are planning to move from colocation to a new data center. In data centers, they ask how many kilowatts we need for our racks.
Is a simple formula enough: W=I*U? I know the number of amperes (I). What is the voltage U in American data centers: 110 or 380 V?
I found the kW <-> kVA concept in this calculator .

UPD1. Is it enough to simply add up the power of all power supplies to get the required value?

PS As an addition, tell me what should be considered when moving to a new DC.

Thanks in advance!

Answer 1

It is better to take the power from the power supplies, the maximum power consumption is indicated there. That is what you should be aiming for.
If you specify a lower value, then there is a chance that your servers at maximum load (for example, when turned on at the same time) will consume exactly the maximum, and this will lead to the shutdown of the machine.

Answer 2

Do you have servers, I hope, connected to UPS? Look at it here. All APCs, even the poorest BackUPS, show the current load. Most likely, it will turn out 5 times less than the stupid summation of the PSU ratings (depends, of course, on the stuffing of the servers).

Answer 3

Most likely DC asks nameplate capacity. Those. how much maximum power will be consumed by the equipment. It will be very difficult to convince the DC that the server will consume 350VA, with the 800VA passparts in any case, it will be very difficult.
Actually, already in the calculation, actual consumption can also be taken into account. But not all DCs have this ... For example, in our DCs , tariffing with measurements of actual consumption on request. But no one has asked yet. :)

Answer 4

There is a technical passport for any device (including power supplies). Google it and you'll find everything.

Answer 5

There is no way to ask the current host? If the servers stick out in some more or less smart PDU, then you can clearly see both Amperes and kW

Answer 6

Well, in American DCs, as a rule, 120V.
If you need a place in an American DC, at a very good price - write :)