What happened to the "new" 1 Tb ones (let's call them disk3 and disk4)? In short nothing and they are each 2TB, total 4TB. Disk 3 and Disk4 are each 2TB are/were not affected by the "calamity" [they were empty]...I used one of them after the event to store an image of Disk2 to try salvage the data. How were the disks originally partitioned (let's call them disk1 and disk2)? The 2 old/small 250GB disks were originally organized as : Disk1, Two partitions A: 21 GB system + B: 212GB data volume ---> 250GB Disk2, Two partitions X: 70 GB data + Y: 160GB data ---> 250GB That would probably happen if you had only two disks connected, but you connected 4 of them, right? No, only two of them were mirrored the other two were/are not part of the array, Now I have moved one of the small disks[mirrored] to my old computer as well as one of new 2TB disks(3) to salvage the data on disk2.[partition Y: is mostly intact, while partition X: is mostly corrupted and is a mirror of A: i.e 21GB with about 50GB empty]