试画出HDFS文件块部署在若干数据节点服务器（DN）上的结构图

以下是HDFS文件块部署在若干数据节点服务器（DN）上的结构图：

        +---------+         +---------+
        |         |         |         |
        |    DN1  |         |   DN2   |
        |         |         |         |
        +----+----+         +----+----+
             |                    |
        +----+----+         +----+----+
        |         |         |         |
        |  b1-1   |         |  b2-1   |
        |         |         |         |
        +----+----+         +----+----+
             |                    |
        +----+----+         +----+----+
        |         |         |         |
        |  b1-2   |         |  b2-2   |
        |         |         |         |
        +----+----+         +----+----+
             |                    |
        +----+----+         +----+----+
        |         |         |         |
        |  b1-3   |         |  b2-3   |
        |         |         |         |
        +---------+         +---------+
             |                    |
        +----+----+         +----+----+
        |         |         |         |
        |  b3-1   |         |  b4-1   |
        |         |         |         |
        +----+----+         +----+----+
             |                    |
        +----+----+         +----+----+
        |         |         |         |
        |  b3-2   |         |  b4-2   |
        |         |         |         |
        +----+----+         +----+----+
             |                    |
        +----+----+         +----+----+
        |         |         |         |
        |  b3-3   |         |  b4-3   |
        |         |         |         |
        +---------+         +---------+
             |                    |
        +----+----+         +----+----+
        |         |         |         |
        |  b5-1   |         |  b5-2   |
        |         |         |         |
        +----+----+         +----+----+
             |                    |
        +----+----+         +----+----+
        |         |         |         |
        |  b5-3   |         |  b5-4   |
        |         |         |         |
        +----+----+         +----+----+
             |                    |
        +----+----+
        |         |
        |  NN     |
        |         |
        +---------+

其中，DN1和DN2为两个数据节点服务器，b1、b2、b3、b4、b5为5个文件块，每个文件块有2个备份副本，分别分布在不同的数据节点上。NN为名称节点服务器，负责管理文件系统的命名空间和客户端的访问请求。