Shulou(Shulou.com)06/03 Report--

Hdfs startup sequence:

1 、 namenode

2 、 datenode

3 、 secondnamenode

4 、 yarn

Webui:

Default is port 50070, dfsheath

Ui content explanation:

ClusterID: generated when namenode is formatted (hdfs namenode-format)

BlockpoolID: block pool

For federation and memory management use. )

Namenode Journal status:

It's the edit log.

Namenode storage:

Image file storage information

Launch the log file directory $HADOOP_HOME/logs:

X.log: log information for most applications through log4j logging

X.out records standard output and standard error logs, with a small number of records

Naming rules for log files:

[frame name-user name-process name-hostname-log format suffix]

Secondary namenode:

1. The client's operation on hdfs will be recorded in the edits file, that is, journal.

2. The content in namenode memory is fsp_w_picpath+edits.

3. After namenode's fsp_w_picpath and edite files are merged regularly, they are synchronized to secondary namenode.

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