Shrinking director_user_expire might be a workaround but not as good as a solution, as also the user can end up mapped to the same server again. Director flush is both manual and aggressive, so not a good solution too.
The possibility to move users between backends without killing existing connections is a good solution, yes! It can be scripted. =] What I suggested was more automated, but that can be left for a future future. If you have a command to be manually issued like: "doveadm director rebalance" it would be great. Thanks for your feedback. Att, Webert de Souza Lima MAV Tecnologia. On Fri, Apr 21, 2017 at 4:52 AM, Timo Sirainen <t...@iki.fi> wrote: > On 20 Apr 2017, at 17.35, Webert de Souza Lima <webert.b...@gmail.com> > wrote: > > > > Hi, > > > > often I run into the situation where a dovecot server goes down for > > maintenance, and all users get concentrated in the remaining dovecot > server > > (considering I have 2 dovecot servers only). > > > > When that dovecot server comes back online, director server will send new > > users to it, but the dovecot server that was up all the time will still > > have tons of clients mapped to it. > > > > I suggest the director servers to always try to balance load between > > servers, in the way: > > > > - if a server has several more connections than other, mark it to > > re-balance > > - when a user connected to this loaded server disconnects, map it to > > another server (that is per definition not the same server) immediately. > > > > that way it would gracefully re-balance, not killing existing > connections, > > just waiting for them to finish. > > You could effectively do this by shrinking the director_user_expire time. > But if it's too low, it causes director to be a bit more inefficient when > assigning users to backends. Also if backends are doing any background work > (e.g. full text search indexing) director might move the user away too > early. But setting it to e.g. 5 minutes would likely help a lot. > > There's of course also the doveadm director flush, which can be used to > move users between backends, but that requires killing the connections for > now. I've some future plans to make it possible to move connections between > backends without disconnecting the IMAP client. >
