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MQTT consumers can share and loadbalance a topic subscription. |
{% hint style="warning" %} Consumer session balancing has been deprecated and will be removed in VerneMQ 2.0. Use Shared Subscriptions instead. {% endhint %}
Sometimes consumers get overwhelmed by the number of messages they receive. VerneMQ can load balance between multiple consumer instances subscribed to the same topic with the same ClientId.
To enable session balancing, activate the following two settings in vernemq.conf
allow_multiple_sessions = on
queue_deliver_mode = balance
{% hint style="info" %} Currently those settings will activate consumer session balancing globally on the respective node. Restricting balancing to specific consumers only, will require a plugin. Note that you cannot balance consumers spread over different cluster nodes. {% endhint %}