Help with RAID

Hello my fellow nerds


It seems that last night one of my 2tb drives failed however I do not have another 2tb I only have a 1tb if I put this in what will happen please help also I am using RAID 5 config



The raid will treat all the drives as 1tb the additional space will not be usable. I imagine there could be other unforeseen issues that ma come up when rebuilding the array.