Add disk to increase storage pool

[Santeau]

Hi,

I have a TNAS model F4-210 running TOS version 4.2.40.

I initially had 1 HDD of 12Tb, but bought another 12tb disk to increase the storage available to 24Tb.
I tried to do that but ended up with the following configuration (see attachment).

I couldn't find an explicit set of instructions on how can I use my two 12Tb hard drives to have 24Tb of storage.
Could you give me a straightforward set of instructions that would attain that desired outcome?

Thanks

[TMroy]

You have set your RAID configuration to RAID 1.
what is RAID 1?

[Santeau]

Yes, thank you for your answer, and sorry for the delay. My storage pool is currently set to RAID 1. I would like to switch to RAID 0. Without losing my data.

Is this possible?