max_message_rate

Since: Version 2024.06.10-84e84b89

The functionality described in this section requires version 2024.06.10-84e84b89 of KumoMTA, or a more recent version.

Optional string.

Specifies the maximum permitted rate at which messages can move from this scheduled queue and into the ready queue for the appropriate egress source.

The value is of the form quantity/period where quantity is a number and period can be a measure of time.

Examples of throttles:

"10/s" -- 10 per second
"10/sec" -- 10 per second
"10/second" -- 10 per second

"50/m" -- 50 per minute
"50/min" -- 50 per minute
"50/minute" -- 50 per minute

"1,000/hr" -- 1000 per hour
"1_000/h" -- 1000 per hour
"1000/hour" -- 1000 per hour

"10_000/d" -- 10,000 per day
"10,000/day" -- 10,000 per day

Throttles are implemented using a Generic Cell Rate Algorithm.

If the throttle is exceeded the message will be re-inserted into the scheduled queue with a delay based on the acceptance rate of the throttle.

This option is distinct from the egress path max_message_rate option in that this one applies to a specific scheduled queue, whilst the egress path option applies to the ready queue for a specific egress path, through which multiple scheduled queues send out to the internet.

If you have configured max_message_rate both here and in an egress path, the effective maximum message rate will be the lesser of the two values; both constraints are applied independently from each other at different stages of processing.