K, I’ve got 4 2GB drives mirrored and welded together with LVM. I backed up everything on the old volume (twice in some cases).
I deleted the old 6.5 TB Volume. That takes balls.
I created a new 1.5TB mirror with two drives and grew the new Volume with the command:
mdadm –create /dev/md3 –level=1 –raid-devices=2 /dev/sd[bc]2
vgextend RaidDataGroup /dev/md3
lvextend -l +5126 /dev/RaidDataGroup/RaidData
I’m now restoring the data.