What is required to enable vSAN encryption on a VxRail cluster?

A VxRail cluster is being deployed in a DMZ environment.
What is the recommended deployment option?

Which step must occur prior to deploying a 2 node VxRail Cluster?

A systems engineer notices that a VxRail host that previously appeared in a cluster within vCenter is now disconnected and is not responding. The VMs that were running on that host have been recovered on other available hosts.
What initial action needs to be done to resolve the issue?

A failure occurs during the deployment of a VxRail cluster. You need to look through the marvin.log file to see what could be causing the error.
Where is this file located?