I have a disk of 500GB (465GB formatted) and one of 80GB (72GB formatted), and I wanted to create a linear array i.e. append the space of both disks with software-managed RAID tool mdadm. The bigger disk has more than 90% occupied and I would want to append the capacity of the smaller disk to it. Can I do it without wiping/backing up my bigger disk? It's not possible for me to back it up. I tried the following command mdadm --create --verbose /dev/md0 --level=linear --raid-devices=2 /dev/sdb /dev/sdcwithin a virtual machine. It creates /dev/md0 as a new block device, but it appears to need format, which, obviously is not what I want to do. Any ideas? Also, I tried this over xubuntu16, but I plan to deploy it over debian 8. I have used mdadm on both of them and it does not appear to be any relevant difference.EDIT: forgot to mention that I'm using NTFS over the main disk.
Create a linear array with RAID over a non-empty disk
linux;raid;mdadm;software raid