In the last weeks I played around with mdadm - on VMs, Odroid-Devices, PCs - all with Debian 10. I observed a (for me) curious behavior about the naming of RAID devices. I did "--create /dev/md0" all the time. But sometimes it results in /dev/md127. Sometimes it is /dev/md/0. Sometimes it switches between upgrade of the kernel image (/dev/md127 become /dev/md0 and booting fails). Googleing this topic brings up a lot of other users discussing about that problem. My current solution is to ignore the /dev/*-name and mount the device/partition by its UUID. Another often reported "solution" is to edit the mdadm.conf. But this is not a good solution for me. mdadm looks in the superblock and knows (nearly) everything. Each conf-file I need to edit keeps the possibility for errors/mistakes/faults (because I am not a sysop/admin but a simple home-server-wannabe-admin). My Question is how this names come up? How does mdadm, the kernel or what ever component is responsible here, decide about the "name" of a raid device? And which factors influence the re-nameing of such devices (e.g. between boot or kernel-updates)?
