On 16/01/2020 20:46 Alexander Dalloz < ad+lists@uni-x.org> wrote:


Am 16.01.2020 um 18:04 schrieb Kishore Potnuru:
I need your help on my issue very badly.

I have the dovecot version 2.0.9 installed on RHEL linux 6.10 version. It's
a single Live server. I need to add a load balancer by adding another
server for resilience.

I cannot upgrade the dovecot version at this time as it is a single live
server. If something goes wrong, I will be in trouble.

Basically the requirement/issue is:

a) it's a single live dovecot POP3/IMAP server
b) people are accessing their emails from microsoft outlook (by giving the
same server name as IMAP and SMTP server). But more than 100000 emails will
be travelled/routed.
c) This server is not rebooted from couple of years.
d) Now they are worried about, just in case if the server is having any
issues during the reboot
or
if something goes wrong with the server in any case, there will be huge
issues.

e) They would like to create resilience by adding another server and emails
will be travelled from both the servers. If one server is having any issues
due to any technical issue and if it doesn't come back easily, then the
emails will be travelled through the other server and there will no
disturbance to the emails. atleast it travels from the other server.

I have very less knowledge on this. Could you please help me providing the
best solution for this.

I will wait for your reply. Please please please help me.

Thanks,
Kishore Potnuru
Don't take it personal Kishore, you probably just inherited that disaster.

RHEL 6.10 is really old and thus your dovecot version ancient and
unsupported by upstream. RHEL 6.10 is going EOL by end of Nov this year.
And I am not sure that system is really a clean 6.10 if it hasn't been
rebooted since several years as you state.

Load balancing will not solve your issue. Migrate away from that host to
a fresh new install with a more current OS and dovecot release. Spin up
the new system, configure dovecot properly, sync the mail over from the
old system to the new one. Plan a maintenance downtime where you do a
final sync and then replace the old host with the new one which you give
the same identity. The downtime will be minimal.

Alexander

This is probably best plan. 
---
Aki Tuomi