[Dovecot] dovecot director service

[Brandon Davidson]

Xavier,

On 7/8/10 1:29 AM, "Xavier Pons" <xavier.pons at uib.es> wrote:
>
> Yes, we will have two hardware balancers in front of proxies. Thus,  the
> director service will detect failures of backend servers and not forward
> sessions them? how detects if a  backend server it's alive or not?

IIRC, it does not detect failures of backend servers. It's up to you to
detect outages and react appropriately.

The folks that sponsored Director development apparently have a monitoring
script that removes downed nodes by running something like 'ssh directorhost
doveadm director remove backendhost', and then re-adds them when they come
back up. 

I'm not sure how I'm going to handle this myself, as our monitoring system
only checks every 5 minutes, and our existing load balancers check and
add/remove nodes every 20 seconds or so. 5 minutes would be a long time to
have Dovecot trying to send users to a non-functional server.

> The command 'doveadm director status', gives information about status of
> backend mailservers or of director servers?

Just the backend servers - it shows backend server addresses and how many
users they're each assigned, or details on a specific user mapping.

I am not aware of a way to get Dovecot to output the director ring status.
That would be nice though, to be able to list the directors and how many
connections they're each proxying.

You might read though this thread, which starts here:
http://www.dovecot.org/list/dovecot/2010-May/049189.html
And continues later here:
http://www.dovecot.org/list/dovecot/2010-June/049425.html

-Brad