private void validateMountPath() {
    if (mountPath == null) {
      throw new IllegalStateException("Mount path cannot be null.");
    }
    if (mountPath.length() == 0) {
      throw new IllegalStateException("Mount path cannot be zero-length string.");
    }
    File mountPathFile = new File(mountPath);
    if (!mountPathFile.isAbsolute()) {
      throw new IllegalStateException("Mount path has to be an absolute path.");
    }
  }
An implementation of {@link DiskId} to be used within the {@link StaticClusterManager}.

A Disk stores {@link Replica}s. Each Disk is hosted on one specific {@link DataNode}. Each Disk is uniquely
identified by its DataNode and mount path (the path to this Disk's device on its DataNode).
ambry-clustermap/src/main/java/com/github/ambry/clustermap/Disk.java