What if to make RAID 1?

Question

RAID

I welcome everyone.
There is a server in which you can select sat modes in the BIOS: IDE, AHCI, RAID.
The server has 2 absolutely identical HDDs installed: 1 with the operating system, 2 with all sorts of data.
If you set the BIOS to RAID mode, then when you reboot, will RAID creation begin, erasing all data from the second disk?
Motherboard supports RAID 1

Answer 1

No, it won't start. You will need to press a certain key or combination to get into the array creation menu and format there.
Please note that the OS will most likely not start, since the RAID drivers are most likely not installed in it.
Without a configured array, the drives will operate in AHCI mode, but a RAID driver is still needed.

Answer 2

Most likely, when RAID is initialized, data will be destroyed on both drives.

Answer 3

erasing all data from the second drive?

Yes, at least both can be overwritten with zeros
See the documentation, but it's better to assume that the operation is destructive for all data on the disks.