void setDefaultStorageGroupLevel(int defaultStorageGroupLevel, boolean startUp) {
    if (defaultStorageGroupLevel < 1) {
      if (startUp) {
        logger.warn(
            "Illegal defaultStorageGroupLevel: {}, should >= 1, use default value 1",
            defaultStorageGroupLevel);
        defaultStorageGroupLevel = 1;
      } else {
        throw new IllegalArgumentException(
            String.format(
                "Illegal defaultStorageGroupLevel: %d, should >= 1", defaultStorageGroupLevel));
      }
    }
    this.defaultStorageGroupLevel = defaultStorageGroupLevel;
  }
if the folders are relative paths, add IOTDB_DATA_HOME as the path prefix
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/conf/IoTDBConfig.java