If your RAID was setup by the BIOS or by an add in card, then any major modern OS should pick it up so long as is has the drivers for the RAID controller. Even if you have to add in the RAID drives later to the OS, it should not effect your data. If you have a hardware RAID the RAID controller manages that RAID not your OS. That being said it is always safest to backup your data.
If your RAID is a software RAID like those created in the OS whether Windows, Linux, or something like FreeNAS the data will be lost.