The first thing to do if you want to obtain safer storage is to keep it in a different VLAN from the rest of the traffic. This will slow down any kind of attack to your storage infrastructure; in fact, it will not be possible for the computing nodes to tap into the storage network.
Tip
Multiple storage systems do not encrypt data between storage nodes, so a completely dedicated (V)LAN is needed for security reasons.
Another thing you should do to improve the security of your system is to run all storage processes with limited root (not root).