kumomta/docs/reference/kumo/configure_redis_throttles.md

kumo.configure_redis_throttles { PARAMS }

Configure the throttle layer to use a Redis data store to manage throttling across multiple MTA nodes.

The redis server must have redis-cell installed for throttles to work in this way.

PARAMS behaves exactly as described in redis.open.

This function should be called only from inside your init event handler.

kumo.on('init', function()
  -- Use shared throttles rather than in-process throttles
  kumo.configure_redis_throttles { node = 'redis://my-redis-host/' }
end)