I own a NAS, which I'm trying to upgrade by installing - most likely - Debian Stretch on it. In itself that's a relatively straightforward task, but there's one thing I'm a bit uncertain about. My NAS has 2 drives in RAID1 configuration, it's an mdraid setup as far as I can tell and because it's configured by some proprietary software currently running on that NAS I'd like to wipe it clean and start anew. I backed up as much data as I could from the NAS on other media, but there's still some stuff I will no doubt lose if I just wipe everything out "the windowsy way". So I started to explore what I can do with my drives to avoid that loss.
My question is this - is it possible to carry out operations in the following way:
- remove one of the drives (let's call it HDD2) from the RAID1 array (does this require any mdraid operations - in theory (marketing theory anyways) the drives in my NAS are hot swappable, but I have not needed to put that assertion to test)
- install Debian on a drive that's not part of the RAID array - let's say an SSD. Wipe out the remaining HDD1 drive and partition it to my liking without yet setting it up as a RAID1 array.
- put the HDD2 back in, and copy whatever I need from that drive to the newly partitioned HDD1
- remove the HDD2 again
- configure mdraid as if HDD1 was the sole drive in a RAID1 array, source which any additional drives would be mirrored from.
- reinsert HDD2 again, this time expecting mdraid to wipe it out and make it a mirror of HDD1.
Does the above make any sense at all? I'm a software developer and not a sysadmin by trade, so I haven't really done any serious administration, but from a purely logical point of view the above scenario should be feasible. Unless of course there's stuff I don't know.
I know that any such operations come with a risk of data loss, but as I said - I've backed up all I could and even borrowed some drives from friends to be able to hold more, but there's still a fair bit I can't cover. Not life-critical stuff so I'd probably take the risk if there was a chance that the above idea could work out fine.