Offsite or offline? Because they are two different things. You state: > It is a design requirement not to have offline storage Then go on to list amateurish

Offsite or offline? Because they are two different things. You state: > It is a design requirement not to have offline storage Then go on to list amateurish hacks like "sever the 5V line" (offline) or "mirror it to the cloud" (this is literally offsite backup). So your plans of action violate the unbreakable requirements you list in the first paragraph. Why not back up to a proper tape robot which can rotate out tapes? Or did someone bid this job for $500? If the requirements are as you state, then you have already failed because if the datacenter is destroyed by fire, flood, power surge, swarm of locusts - or disk corruption, filesystem corruption, bad RAID controller firmware, etc.... you are, in a word, fucked. All that said, the best way to address ransomware is to prevent it from getting into your network in the first place. Which usually happens via unsecured endpoints manned by idiots. Application whitelisting can help with this.