code: public static StorageTier newStorageTier(String tierAlias)
        throws BlockAlreadyExistsException, IOException, WorkerOutOfSpaceException {
      StorageTier ret = new StorageTier(tierAlias);
      ret.initStorageTier();
      return ret;
    }
docs: Factory method to create {@link StorageTier}.
  
  @param tierAlias the tier alias
  @return a new storage tier
  @throws BlockAlreadyExistsException if the tier already exists
  @throws WorkerOutOfSpaceException if there is not enough space available