public Disk findDisk(String hostname, int port, String mountPath) {
    DataNode dataNode = findDataNode(hostname, port);
    if (dataNode != null) {
      for (Disk disk : dataNode.getDisks()) {
        if (disk.getMountPath().equals(mountPath)) {
          return disk;
        }
      }
    }
    return null;
  }
Finds Disk by hostname, port, and mount path.

@param hostname of datanode
@param port of datanode
@param mountPath of disk
@return Disk or null if not found.
ambry-clustermap/src/main/java/com/github/ambry/clustermap/HardwareLayout.java