Correct connection of servers to the UPS?

Question

Batteries

Good afternoon, dear habrosoobschestvo.
There is a small park of servers (8 pcs.) and 7 UPSs with them. Because almost all servers have several power supplies, we decided to connect each server to several UPSs so that if one of the UPSs fails (for example, a battery dies or electronics fails), the servers do not turn off unexpectedly due to power surges or short-term power outages. The connection diagram is shown below:

White rectangles - UPSS. All APCSmart-UPS. The specific model is shown in the diagram.
Red circles are servers with 1 PSU.
White circles - servers with 2 PSUs operating in 1 + 1 mode (both work simultaneously, with load balancing)
Green circles - servers with 3 PSUs operating in 2 + 1 mode (3 work simultaneously, if one fails, then the other 2 take the load. It also seems to work with one power supply, but knowledgeable people say that this is wrong and can lead to problems)
Black arrows - connect power cables from servers to UPSs.
Red arrows - connect USB cables from computers to ups. Through these cables, the UPS communicates with the server and, for example, sends it to turn off if the battery charge is below a certain level.
I would like to know if there is any sense in such a cross connection, if someone did this and what are the pitfalls.
thanks for the help

Answer 1

There is definitely meaning. Especially if you approach the operation of ups correctly. After all, you need to do periodic checks with them, to carry out a charge-discharge cycle of the battery. If the services are critical, then this is quite logical, since you will turn off one UPS for procedures, and the servers will work from another. But connecting the server with three power supplies already seems superfluous to me.

Answer 2

It makes sense, I did it. The main thing is to calculate the load correctly. For each UPS, consider the load on the connected equipment, taking into account the fact that a backup is required. And yes, it is necessary to do the idea of ​​replacing the elements every couple of years.
But with a USB connection like yours, it's not entirely clear.
For example, if UPS2 is turned off, for example, for prevention, and the electricity is cut, then Serv3 will not receive an alert about a drop in charge from UPS3, but it will receive Serv4, which actually goes to sleep safely. At the same time, Serv3 will go to sleep suddenly and unexpectedly for him. And the same with the rest. Therefore, I would probably think about how to implement it correctly. Either programmatically, or through COM-hub, or somehow else.

Answer 3

I would add a third UPS to the Serv7 + Serv8 bundle so that everything is even.