Hi All,

I request your help on this.

I have 2 dovecot test servers (IMAP protocol) installed with the following configuration.
=============
[root@devap01 ~]# cat /etc/redhat-*
Red Hat Enterprise Linux Server release 6.10 (Santiago)

[root@devap01 ~]# dovecot --version
2.0.9

[root@devap01 ~]# postconf | grep mail_version
mail_version = 2.6.6
===============

I have another server also "devap02" with the same configuration.

Couple of points/questions/queries here.

1. I know these servers are having old dovecot versions. I would like to upgrade to the latest versions. Could you please suggest the steps for upgrading to the latest version in redhat (step by step details are helpful please) . If I upgrade to the latest version, will there be any impact on the existing configuration/setup?


2. Now I have added these 2 servers behind the Load Balancer. Enabled 110/143 ports on the Load Balancer FQDN (test.pop3.testing.com) and opened the firewall ports. Here I configured IMAP settings from microsoft outlook to see the emails. I gave the Incoming Mail Server & Outgoing mail server as "test.pop3.testing.com". It is configured without errors in Outlook. But I see these 2 types issues (shared storage & individual storage)

   a) individual separate storage - When I send 10 emails to LB FQDN (test.pop3.testing.com), the emails are going to 2 backend servers. But when i see the emails from Outlook inbox, it shows 5 emails from one server for some time. After sometime it shows other 5 emails in the inbox. But, I am not able to see all 10 emails at same time in my inbox. Please suggest how to fix this issue? In this scenario, I have separate individual storage in both the servers.

   b) common shared storage - I have tried a different scenario also. I also have one common NFS storage. So, I have configured that storage in both the servers. So when I sent 10 emails, I see all the 10 emails from both the servers as it is common shared storage. But, I am not getting those 10 emails delivered into my Outlook. I have made all the configuration correctly. Please suggest what is the mistake here.     

Dovecot.conf
=========================================================

[root@devap01 ~]# cat /etc/dovecot/dovecot.conf
disable_plaintext_auth = no

listen = *
log_path = /var/log/dovecot.log
mail_location = maildir:/r3/mail/virtual/%d/%n/Maildir/
passdb {
args = /etc/dovecot/passwd
driver = passwd-file
}
pop3_uidl_format = %g
protocols = imap pop3
ssl = yes
ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
ssl_key = </etc/pki/dovecot/private/dovecot.pem

userdb {
args = uid=vmail gid=vmail home=/r3/mail/virtual/%d/%n
driver = static
}
mail_debug = no
verbose_ssl = no
=========================================================

Please help me here.

Thanks,
Kishore Potnuru