《大数据： Hadoop（HDFS） 读写数据流程分析》
本文共 269 字，大约阅读时间需要 1 分钟。
一、HDFS的写数据正常流程
- ①. 服务端启动HDFS中的NN和DN进程
- ②. 客户端创建一个分布式文件系统客户端，由客户端向NN发送请求，请求上传文件
- ③. NN处理请求，检查客户端是否有权限上传，路径是否合法等
- ④. 检查通过，NN响应客户端可以上传
- ⑤. 客户端根据自己设置的块大小，开始上传第一个块，默认0-128M,NN根据客户端上传文件的副本数(默认为3)，根据机架感知策略选取指定数量的DN节点返回
- ⑥. 客户端根据返回的DN1,DN2,DN3节点，请求建立传输通道客户端向最近(网络举例最近)的DN1节点发起通道建立请求，
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