General Backend Settings

protocols = imap pop3 lmtp sieve

Protocols to enable.

verbose_proctitle = yes

Show state information in process titles (in ps output).

mail_log_prefix = "%s(%u)<%{session}>: "

Include the session string in all log messages to make it easier to match log lines together.

shutdown_clients = yes

By default all active sessions will be shut down when dovecot is reloaded or restarted. Setting this to no is dangerous on backend as existing sessions are then not killed when dovecot is restarted or reloaded. This can have serious consequences if for example storage-related settings are changed, as user connection will be using both old and new configuration at the same time.

import_environment = $import_environment MALLOC_MMAP_THRESHOLD_=131072

Allocate all memory larger than 128 kB using mmap(). This allows the OS to free the memory afterwards. This is important for backends because there can be a lot of long-running imap and pop3 processes.