A note on reusing my old hard-drives from mdadm raid10 array in a new raid0 array after buying more hard drives (goo.gl/grFMSE).
Ideally this command should remove the superblock from old disks
sudo mdadm --zero-superblock /dev/sdcBut in practice I faced a problem, when only after something of this sort (goo.gl/o4r8CS)
dd bs=512 count=63 if=/dev/zero of=/dev/sdaraid arrays started properly on reboot. This happened to both old raid10 disks and a disk that was used as plain storage. Magic.
Ofc you can shred and fill the whole disk with zeros, but it takes a lot of time...
sudo shred -v -n1 -z /dev/sda
Linux's madam utility can be used to turn a group of underlying storage devices into different types of RAID arrays. This provides various advantages depending on which RAID level is used. This guide will cover how to set up devices in the most common