redis and cluster | Mar 13, 2016 • Ding Jiao

In Redis Cluster, each node keeps track of which master is serving a particular hash slot.

The DELSLOTS command asks a particular Redis Cluster node to forget which master is serving the hash slots specified as arguments.

In the context of a node that has received a DELSLOTS command and has consequently removed the associations for the passed hash slots, we say those hash slots are unbound. Note that the existence of unbound hash slots occurs naturally when a node has not been configured to handle them (something that can be done with the ADDSLOTS command) and if it has not received any information about who owns those hash slots (something that it can learn from heartbeat or update messages).

If a node with unbound hash slots receives a heartbeat packet from another node that claims to be the owner of some of those hash slots, the association is established instantly. Moreover, if a heartbeat or update message is received with a configuration epoch greater than the node’s own, the association is re-established.

However, note that:

  1. The command only works if all the specified slots are already associated with some node.
  2. The command fails if the same slot is specified multiple times.
  3. As a side effect of the command execution, the node may go into down state because not all hash slots are covered.


The following command removes the association for slots 5000 and 5001 from the node receiving the command:


Usage in Redis Cluster

This command only works in cluster mode and may be useful for debugging and in order to manually orchestrate a cluster configuration when a new cluster is created. It is currently not used by redis-trib, and mainly exists for API completeness.


@simple-string-reply: OK if the command was successful. Otherwise an error is returned.