Setting concurrent IMAP connection limit

[Interkey JeffG]

Mozilla Thunderbird comes by default with its IMAP concurrent connection limit set to 5. This breaks Zimbra (as well as Courier-IMAP, and probably other IMAP servers) unless this is throttled back on the client or increased on the server. However, we're a service provider. We'd like to offer Zimbra to our customers without requiring them to dig around in preferences files for popular applications to make changes allowing the service they're paying for to work. Is there a preference anywhere I can set to change the concurrent connection limit?

[KevinH]

Yes in the admin UI you can set the max threads.

[Interkey JeffG]

Originally Posted by KevinH

Yes in the admin UI you can set the max threads.

D'oh, I didn't think to look under the server properties instead of the Global Settings.

[wdimmit]

Is the "Number of Threads" setting equivelent to max concurrent imap connections per (user/ip), or total concurrent connections? I've got it set to 10 on one of my servers and am still having Thunderbird die on me (connection to server timed out) when moving large numbers of messages.

--Will

[schemers]

total concurrent IMAP connections. The next major release we do should have the Java NIO IMAP server enabled, which doesn't use a thread-per connection and scales much better.

[wdimmit]

Is there a point above which this setting generally causes problems? And / or is there a good procedure for finding the "right" setting aside from creeping the number of threads up every time I see a timeout?

--Will

[KevinH]

If you've got plenty of RAM then your limit would be higher. How many IMAP users do you have concurrently at a time? Might help to start from your needs rather than look for a max. 10 seems really low as each Thunderbird by default can make up to 5 connections. Another idea would be to tweak Thunderbird so it doesn't use as many connections.