Removing DDS nodes from a Cassandra cluster
This content applies only to On-premises and Client-managed cloud environments
Reduce the size of a Cassandra cluster by permanently removing Decision Data Store (DDS) nodes from the cluster. This procedure allows the cluster to rebalance itself and ensures that the removed nodes are not reintroduced into the cluster.
- Run the nodetool utility from any machine in the Cassandra cluster.
- Run a parallel repair on the node to repair and correctly replicate the data
owned by the node:
nodetool repair -par - Remove the node:
nodetool removenode <ID>where ID is the ID of the node that you want to remove. You can view the node ID by running the
nodetool statuscommand. - Perform a graceful shutdown of the Pega Java virtual machine (JVM).
- If there are other services than DDS on the node, and the node still needs to
be part of the Pega cluster, remove the DDS
entry from the
NodeTypesetting on the node. - Restart the Pega JVM.
- Repair and clean up the remaining nodes:
- Run a parallel repair on each remaining node to ensure that any data
that was not replicated for any reason during the removal is repaired
and replicated correctly:
nodetool repair -par - Run a cleanup on each remaining node to remove any data that no longer
belongs to the nodes:
nodetool cleanup
- Run a parallel repair on each remaining node to ensure that any data
that was not replicated for any reason during the removal is repaired
and replicated correctly:
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