Offsite backup is not an overkill! Your HDDs can be lost in burglary, water or fire. B2 is cheap, go for it, you may regret not having offsite backup one day. A

Offsite backup is not an overkill! Your HDDs can be lost in burglary, water or fire. B2 is cheap, go for it, you may regret not having offsite backup one day. And it does not require much effort, tools like Duplicati can automatically encrypt the data and send it to B2.