Properly configure BIOS SD mirroring

Hi,

I have a bunch of R640 which run the open-source oVirt OS for virtualization.

The OS is physically hosted on 1 SD card, which is mirrored on a second one.

The corresponding IDRAC setting is shown below, in "configuration/BIOS settings/integrated devices" in IDRAC9:

My question is about the redundant OS control at the same location:

It is currently set to "None".

Should I set it to "internal SD card" - the idea behind this configuration would be that in case of a failure of one of the 2 SD cards, the OS should be able to boot on the remaining one.

It is not very clear to me which setting to apply.

Thx in advance for any advice.