Is there a RAID type that will allow me to have four hard drives in a NAS, of which two are 6TB, and two are 4TB, and have it set up so that I can use 10TB to save all my files to, and it copies it to the other 10TB? I couldn't find out how to arrange it in that way, using two drives as the storage capacity, and two as the backup.
Synology's RAID calculator didn't seem to suggest it was possible - https://www.synology.com/en-uk/support/RAID_calculator
SRAdmin, when you say use the 2-bay as a replicated copy elsewhere, how would I do that? Would I need to set up some sort of web service to copy my data from the 4-bay NAS to the 2-bay NAS? Wouldn't that be very slow, i.e., as slow as my internet connection? Any useful guides on this would be great.