[Dovecot] Dovecot performance under high load (vs. Courier)

[Timo Sirainen]

On 22.6.2012, at 8.27, email builder wrote:

> So really, a new process is created under *two* circumstances?  1. when a
> process reaches client_limit number of *simultaneous* connections or  2. when
> a process has serviced service_count number of connections.  Is this correct?

Yes.

> So for service *-login, is it OK to do something like service_count=5000, client_limit=2000

It would work, but for login processes the service_count can be 0. I haven't seen them leaking any memory recently.

One somewhat annoying thing with service_count>1 is that the processes have to wait until all of the connections have disconnected before shutting down. For processes handling long running connections (especially IMAP) this can mean that you'll end up with a lot of processes that are ready to shutdown but a couple of connections prevent it from doing this.