hadoop namenode 格式到底是什么? [英] What exactly is hadoop namenode formatting?

问题描述

namenode 格式化究竟涉及什么.如果我在我的 hadoop 安装文件夹中的终端中输入以下命令:

What exactly is involved in namenode formatting. If I type in the following command into my terminal within my hadoop installation folder:

  bin/hadoop namenode -format

它究竟完成了什么?我希望了解名称节点格式的原则和它的意义.谢谢...

What exactly does it accomplish? I am looking to understand principles of namenode formatting & its significance. Thanks...

推荐答案

Hadoop NameNode 是 HDFS 文件系统的集中位置，它保存文件系统中所有文件的目录树，并在整个集群中跟踪文件数据的位置保持.简而言之，它保留了与数据节点相关的元数据.当我们格式化 namenode 时，它​​会格式化与数据节点相关的元数据.这样一来，数据节点上的所有信息都会丢失，并且可以重新用于新数据.

Hadoop NameNode is the centralized place of an HDFS file system which keeps the directory tree of all files in the file system, and tracks where across the cluster the file data is kept. In short, it keeps the metadata related to datanodes. When we format namenode it formats the meta-data related to data-nodes. By doing that, all the information on the datanodes are lost and they can be reused for new data.

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