I/O redirection is done inside the vSphere VAIO libraries, each ESXi will have a connector where our software, being VAIO compliant, will be able to connect and retrieve a copy of each IO for VMs that are selected to be protected with CDP. So write IO will be technically split, one copy to the underlying storage, the other to our sofware. That's why we don't need access to the underlying storage.
EMEA Cloud Architect @ Veeam Software
Veeam VMCE #1