Может ли два диска подключаться через USB-концентратор обходить компьютер при совместном использовании данных?

If I connect two USB drives to an external hub and I copy data from one drive to the other, does the data go through the computer or will the USB hub manage the data? Does this have some performance benefit?

No, this will not work. All the data you are copying will need to be read by the computer from the source drive before it is copied to the target drive.

If anything, having two hard-drives connected to the same USB hub might slow things down. If you have multiple devices connected to the hub, they have to share the bandwidth.

USB is a host-driven protocol, not a peer-to-peer standard like firewire. Drives are just devices, they are not hosts that control or decide anything. Without the host, they cannot even interact with the outside world.

Assuming that you can connect the two drives like that, how will they know which files and/or folders you want to copy? How will they know which drive to copy from and will they overwrite duplicated files? How will they behave if the drives are full?

A USB hub is just a way to share a connection to the computer when you do not have enough USB ports for all the devices you want to connect. Devices connected to the computer through a USB hub never talk to each other. The USB hub ensures that traffic between the computer and the connected devices goes to and from the right device as if each was literally connected to a USB port on the computer.

There is no performance benefit and there may be a performance detriment. The USB hub itself is connected to the computer through a USB connection, so everything connected to the USB hub has to share the bandwidth of that connection. Hard-drives can consume a lot of the USB hub’s bandwidth and affect the performance of other devices attached to the USB hub. You generally do not want to connect hard-drives through a USB hub at all because of that.