High Availability Cluster without Shared Storage

Hi Experts, 

I've been doing some research on how to achieve this goal and what's the best practice.

We are planning to do a high availability cluster for our server running the following services.

1. Active Directory
2. DNS and DHCP
3. File Server

Currently we have one fully operational Windows server 2016 running in Dell R530. Since we have 2 set of dell server, we want to configure a HA cluster for downtime protection. And  we want to set it up in a way were we have a main server that will be doing all the workload and a backup server that will replace the main if it fail without downtime.

But most common reference I found related to our goal involved a shared network. Now what I wanted to know are:

• Why is it recommended to have a shared storage 
• Is it possible to configure HA without shared storage
• If possible, what are the risk of not having a shared storage

Thank you in advance experts.