int getResourceExpectedTotalDiskCapacityUsage(String resource, int replicationFactor) {
    String dcName = clusterMapConfig.clusterMapDatacenterName;
    getResourceConfig(resource, dcName);
    int result = 0;
    for (String partition : resourceNameToPartitionByDc.get(dcName).get(resource)) {
      result += getPartitionDiskWeight(partition) * replicationFactor;
    }
    return result;
  }
Callback method when this data node is becoming SEMI AUTO from FULL AUTO.
ambry-clustermap/src/main/java/com/github/ambry/clustermap/HelixClusterManager.java