Where is Drive 2?

I am using G-raid 12tb thunderbolt 3. where is disk 2 in raid 1 array

i configured as raid 1. disk capacity reduced to 6tb. where is the other 6tb. i understand same files will be copied to disk 2. but how to access disk 2 ? what is the procedure if disk failure and to recover files from disk 2 if disk 1 is failed ?

The other drive is hidden, that is how RAID works. The computer cannot tell the unit has 2 drives in it. You cannot access the 2nd drive.

If one fails the other takes over and continues to mount and be usable that is how the mirror functions.