diff --git a/docs/user-manual/en/clusters.md b/docs/user-manual/en/clusters.md index 5224e808e0..59b23f34c5 100644 --- a/docs/user-manual/en/clusters.md +++ b/docs/user-manual/en/clusters.md @@ -938,27 +938,69 @@ nodes) the messages on those nodes would be lost unless the broker sent them to another node in the cluster. Apache ActiveMQ Artemis can be configured to do just that. -The simplest way to enable this behavior is to set `scale-down` to -`true`. If the server is clustered and `scale-down` is `true` then when -the server is shutdown gracefully (i.e. stopped without crashing) it -will find another node in the cluster and send *all* of its messages -(both durable and non-durable) to that node. The messages are processed -in order and go to the *back* of the respective queues on the other node -(just as if the messages were sent from an external client for the first -time). +To enable this behavior configure `scale-down` in the `live-only` +`ha-policy`, e.g.: -If more control over where the messages go is required then specify -`scale-down-group-name`. Messages will only be sent to another node in -the cluster that uses the same `scale-down-group-name` as the server -being shutdown. +```xml + + + + true + + + + +``` +If `scale-down`/`enabled` is `true` then when the server is shutdown +gracefully (i.e. stopped without crashing) it will find another node in +the cluster and send *all* of its messages (both durable and non-durable) +to that node. The messages are processed in order and go to the *back* of +the respective queues on the other node (just as if the messages were +sent from an external client for the first time). + +The _target_ of the scale down operation can be configured a few differnt +ways. The above example uses `discovery-group-ref` to reference a +`discovery-group` which will be used to find the target broker. This +should be the same `discovery-group` referenced by your `cluster-connection`. +You can also specify a static list of `connector` elements, e.g.: + +```xml + + ... + tcp://server0:61616 + +... + + + + true + + server0-connector + + + + +``` + +It's also possible to specify `group-name`. If this is specified then +messages will only be sent to another node in the cluster that uses the +same `group-name` as the server being shutdown, e.g.: + +```xml + + + + true + my-group + + + + +``` > **Warning** > > If cluster nodes are grouped together with different -> `scale-down-group-name` values beware. If all the nodes in a single +> `group-name` values beware. If all the nodes in a single > group are shut down then the messages from that node/group will be > lost. - -If the server is using multiple `cluster-connection` then use -`scale-down-clustername` to identify the name of the -`cluster-connection` which should be used for scaling down.