A systems administrator is deploying a new server that will host a mission-critical application requiring the highest possible uptime. The server is equipped with two hot-swappable, redundant Power Supply Units (PSUs). The server rack provides two independent Power Distribution Units (PDUs), each connected to a separate Uninterruptible Power Supply (UPS). Each UPS is supplied by a different electrical circuit. To maximize fault tolerance, which of the following represents the BEST power configuration for this server?
Connect both PSUs to separate outlets on the same PDU.
Connect one PSU to a PDU fed by a UPS and the other PSU directly to a wall outlet on a separate circuit.
Connect one PSU to a PDU and leave the second PSU disconnected to serve as a cold spare.
Connect one PSU to the first PDU and the second PSU to the second PDU.
The correct approach is to connect one PSU to the first PDU and the second PSU to the second PDU. This configuration ensures maximum fault tolerance by creating two completely independent power paths from the server to the building's electrical circuits. If any single component in one power path fails (PSU, PDU, UPS, or circuit), the other path will continue to supply power to the server, preventing downtime. Connecting both PSUs to the same PDU, even on different outlets, makes that PDU a single point of failure. Connecting one PSU to a UPS and the other directly to wall power provides unbalanced protection and is not a best practice, as the unprotected PSU is vulnerable to surges and outages. Leaving one PSU disconnected negates the benefit of active redundancy, as it cannot take over instantly in case of a failure.