Edit: I think I misinterpreted your request... you CANNOT have offline storage? Then ignore the following lines :-) Get a server with ECC RAM and storage Get

Edit: I think I misinterpreted your request... you CANNOT have offline storage? Then ignore the following lines :-) Get a server with ECC RAM and storage Get TrueNAS Configure an ecrypted ZFS pool Configure shares (NFS, Samba, etc.) Configure periodic ZFS snapshots (hourly, daily, weekly, etc) Connect your shares from clients Use cloud providers /offsite that support zfs send and configure them Test a disaster regularly and take notes on how to perform a restore as fast as possible Do not ever login, store or input server credentials or unlock keys on your clients (otherwise ransomware may access your snapshots) If ransomware attacks you, restore your latest snapshot That should work