If it fails, I will just throw in a new SSD and redo the backup. I sometimes delete everything and redo it anyway, for various reasons. In any case, I usually have all copies of all files on the original drive, as local backup on the device and backup on the workstation. And even if those three should fail - which I will immediately know, due to monitoring the systemd job - I still have daily backups on two different, global hosters as well as the seperate NAS. The only case in which all full backups would be affected would be a global destruction of all electronics due to solar storms or a general destruction of earth, in which case that's the least of my problems. And in case the house burns down, and I only have the daily backups, potentially losing 24 hours of data, that's also the least of my problems. Yes, generally using Raid 5 for backups is better, but in my case I have multiple copies of the same data at all times, surpassing the 321 rule (by far - 622, and soon 623). As all of my devices are connected via Gigabit, getting backups from eg. the workstation after the PC (with backups) died is just as fast as getting backups from the local PC backup Raid itself. And using Raid 0 is better (in speeds) than just slapping them together in series.