Which of the following should be unique when installing dual controller heads?

Rack location refers to the physical placement, which does not need to be unique for dual controllers as they are often co-located.

Dual controller heads typically run the same firmware version to ensure compatibility and consistent operation across the high-availability pair.

While an alias can be unique for identification, the underlying network identifier (IP address) is fundamentally what must be unique for network communication.

Each controller head requires a distinct IP address to be uniquely identified on the network, allowing devices to communicate with the correct controller without conflicts. This is fundamental for network-accessible storage systems to operate independently or as a high-availability pair.