[Veserv]

That does not work. They just infect you and do not demand a ransom for a few months as they encrypt all your data going to the backup. Now your backups are also encrypted going back multiple months and you have to discard months of work.

[ArcHound]

I guess I should set up a monitor alerting me if the two backup diffs are larger than 80% of the data size.

But yes, these are the practical problems we need to address.