  Control delivery rates
  Cristiano Otto Von Trompczynski


     IInniittiiaall ddeessttiinnaattiioonn ccoonnccuurrrreennccyy
        The "Initial destination concurrency" option specifies the
        initial per-destination concurrency level for parallel delivery
        to the same destination. This limit applies to delivery via
        SMTP, via the local delivery agent and via the pipe mailer.

        With concurrency of 1, one bad message is enough to block all
        mail to a site. A concurrency of 2 seems a reasonable choice.
        This option sets the "initial_destination_concurrency" postfix
        variable.


     MMaaxxiimmaall bbaacckkooffff ttiimmee
        The "Maximal backoff time" option specifies the maximal time in
        seconds between attempts to deliver a deferred message.  This
        option sets the "maximal_backoff_time" postfix variable.


     MMaaxxiimmaall qquueeuuee lliiffeettiimmee
        The "Maximal queue lifetime" option specifies the maximal time
        in days a message is queued before it is sent back as
        undeliverable.  This option sets the "maximal_queue_lifetime"
        postfix variable.


     MMiinniimmaall bbaacckkooffff ttiimmee
        The "Minimal backoff time" option specifies the minimal time in
        seconds between attempts to deliver a deferred message.  This
        parameter also limits the time an unreachable destination is
        kept in the short-term, in-memory destination status cache.
        This option sets the "minimal_backoff_time" postfix variable.


     QQuueeuuee rruunn ddeellaayy
        The "Queue run delay" option specifies the time in seconds
        between deferred queue scans by the queue manager.  This option
        sets the "queue_run_delay" postfix variable.


     DDeeffeerr ttrraannssppoorrttss
        The "Defer transports" option specifies the names of transports
        that should not be delivered to unless someone issues "sendmail
        -q" or equivalent. Specify zero or more names of mail delivery
        transports names that appear in the first field of master.cf).
        This option sets the "defer_transports" postfix variable.