I've just bought two 1.5TB disks with the aim of creating a 1.5TB RAID1 array.
In my infinite lack of wisdom (and a lack of space inside the computer - it already had 6 disks), I stuck one in, formatted it to EXT4 and proceeded to copy data all over it from drives that I'm subbing out.
Now I want to create a mdadm RAID1 array with its twin disk. I thought this was possible. Probably involving unmounting and
dding the content across but I'm sure I saw this somewhere before...
But I can't find the tutorial I used the last time I was setting up mdadm so I'm scared. I don't want to nuke 800gigs of data.