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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 What exactly does it accomplish? I am looking to understand principles of namenode formatting & its significance. Thanks...
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Formatting the namenode deletes the information from namenode directory. The NameNode directory is specified in hdfs-site. xml file in dfs. namenode.
Answer (1) Hadoop Namenode is used to specify the default file system and also the defaults of your local file system.So, you need to set it to a HDFS address. This is essential for configuration of client and your Local File system. filesystem.
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.
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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hadoop namenode -format formats your file system at the location specified in hdfs-site.xml
here my namenode directory is /usr/local/hadoop/dfs/name
<property> <name>dfs.name.dir</name> <value>/usr/local/hadoop/dfs/name</value> <final>true</final> </property> If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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