I have a DS220+ with 2 identical drives, configured as RAID, so just one volume. Everything was working great, but to access the new object-recognition in photos, I added RAM, which caused some corruption and now the volume is read-only and won’t repair itself (even after removing the RAM). So now I’m preparing to do an external backup and rebuild the NAS. But now I’m wondering: If volume issues are more likely than drive issues, should I forget about RAID, create one volume on each drive, and use the second volume as a local backup? Or is RAID still the best first line of defence? (Or is there a way I can do both with two drives?
another advantage is not needing to restore from backup when one drive fails. RAID5 oder 6 would be better but does need more than two drives, so with only two RAID1, snapshots and backup of those snapshots is best (0.02€)