I have the test environment with the same configuration. But I have been asked to go with same environment for HA/Resilience in Live.

Yes, I have only one Live server. It is configured in "Maildir" format. The data stores on a Network / Shared Storage (But definitely not local disk, its a mount point).

I have been asked to create a HA/Resilience for this environment. They gave me another server with same ram/cpu/os and I need to configure the dovecot on it.

Please provide your suggestions/steps as I am new to this kind of environment.

Is it possible, when any email comes to any one or both of the two servers, how it will be read by the user from Outlook? How to create the environment?