Decommissioning a datacenter 

Steps to properly remove a datacenter so no information is lost.

Steps to properly remove a datacenter so no information is lost.

Procedure

  1. Make sure no clients are still writing to any nodes in the datacenter.
  2. Run a full repair with nodetool repair.

    This ensures that all data is propagated from the datacenter being decommissioned.

  3. Change all keyspaces so they no longer reference the datacenter being removed.
  4. Run nodetool decommission on every node in the datacenter being removed.