@Override
  public String toString() {
    return "ioengine=" + this.getClass().getSimpleName() + ", paths=" + Arrays.asList(filePaths)
      + ", capacity=" + String.format("%,d", this.capacity);
  }
IO engine that stores data to a file on the local file system.
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/FileIOEngine.java