Testing DVD-R and CD-R 25 years later: optical disks from Japan

IMO the only way to perfectly protect yourself against Ransomware Attacks is with CD-Rs, because it's something not even hardware can alter. A skilled take over of the root level of a machine can be encrypting everything and you'd never know it, until the day it denies your access, by deleting an encryption key until you pay up to get it back...you hope.

Modern backup systems use reference counting mechanisms, which means you can set up any old versions policy you want. Something like "last 3 annual backups + last 12 monthly ones + last 8 weekly ones + last 30 daily ones" will help a lot against slow encryptors.

You'll want to ensure the malware can't destroy your backup, but that is possible too. A traditional way is to have a separate backup machine that runs backup program and pulls files remotely. Some backup apps can store directly to cloud storage and can work with "append only" permissions, to ensure that client can't delete existing backups. In this configuration, a separate trusted machine must run pruning periodically.

That's all true, and probably a better system overall, but burning an optical disk, labelling it, and putting it on a shelf does feel like a more accessible backup regime for many people. :-)