Hello,

you need to "clone" the first server, change the ip address, mount the same maildir storage and use some mechanism to share the accounts database.

Then you need to put a TCP load-balancer in front of the servers an you are good to go. This is the easiest solution if you already have in the network an appliance that can do LB. For instance if you already have a firewall with that function.

Another solution is to make a cluster with corosync/pacemaker out of the two servers:

https://www.digitalocean.com/community/tutorials/how-to-create-a-high-availability-setup-with-corosync-pacemaker-and-floating-ips-on-ubuntu-14-04

https://linuxacademy.com/blog/linux-academy/configure-a-failover-cluster-with-pacemaker/

Thank you all for the replies.... 

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? 

Thanks,

Kishore Potnuru

On Fri, Jan 10, 2020 at 7:55 AM Sami Ketola <sami.ketola@dovecot.fi> wrote:

> On 10 Jan 2020, at 9.20, Emmanuel Dreyfus <manu@netbsd.org> wrote:
>
> On Fri, Jan 10, 2020 at 09:07:24AM +0200, Aki Tuomi wrote:
>> Replication is not supported with mbox. Most features are not.
>
> It would be nice if the document about replication could tell
> what setup works.


First step in setting up HA system would be to migrate away from mbox.

Sami

-- 
Best regards,
Adrian Minta