Individual_Brick5537B

Many storage systems have features called “data scrubbing” https://en.wikipedia.org/wiki/Data_scrubbing , which Synology discusses here: https://blog.synology.com/how-data-scrubbing-protects-against-data-corruption

This will correct errors with drives, and potentially give some early warning that a drive may fail. You will also want to run SMART tests on your drives. Quick tests often (I do daily), extended tests occasionally (I do monthly).

The backup software should also have a way to verify the accuracy of the data, and check that the data can be restored. On Synology, HyperBackup has backup integrity check https://kb.synology.com/en-us/DSM/tutorial/What_is_backup_integrity_check_for_Hyper_Backup_tasks .

Safe deposit box, 8TB external drive with encrypted backups of my NAS. Have the same drive locally too and swap them monthly. Current year and prior year folders also get cloud backed up to backblaze.