I will buy a motherboard AsRock H370M-ITX miniITX to mount a Nas that will run Ubuntu 18.04.

This motherboard can do RAID 0, 1, 5 and 10.

I would like to know how it works and what happens when you reinstall the OS:
Should we rebuild the RAID?
Should we start from scratch and recreate the RAID and copy the data?

I ask the question because so far I have done only software RAID Windows (mirrored disk) and it was necessary to start from scratch with the reinstallation of Windows.

Thanks for your help.