[Dovecot] Dovecot design-question
lists at wildgooses.com
Wed Feb 17 20:38:38 EET 2010
On 01/02/2010 10:05, Werner wrote:
> Hi everybody,
> we're currently in the process of drafting our new mailserver-setup.
> Instead of a single-server-setup we'd like to have two equal servers
> behind a loadbalancer like LVS and shared mailhomes on NFS.
> We'd like to use dovecot for POP/IMAP, dovecot-deliver as LDA.
> - It's probably the best idea to direct SMTP and POP/IMAP always to
> the same server behind the loadbalancer (because dovecot-deliver is
> used which updates indexes?)
> - If we think of a "active/passive" setup: dovecot index-files locally
> or on the nfs-share?
At least one other user on the list had success using Dovecot proxy and
a "backend servers are the frontend servers" setup. Basically the user
comes into a random frontend server, the dovecot proxy has a 50:50
chance to discover they are already on the right machine and gets out of
the way, otherwise it proxy's the connection to the other machine.
I guess this will waste 25% internal bandwidth on average (external b/w
should remain the same). Apparently cpu requirements are very low for
proxying and additional memory requirements can be measured, but may be
If one server fails then you have to update the loadbalancer to redirect
only to the working server AND update the proxy not to try and send
users to the other machine. Depending how you configure things this
extra step can be done very easily though.
More information about the dovecot