A number of configuration parameters are listed
Where red is configured to have parameters configured
Parameter value Comment
Fs.default.name |
The URI of the NameNode. |
HDFS://Host name/ |
Dfs.hosts/dfs.hosts.exclude |
License/Deny Datanode list. |
If necessary, use this file to control the list of licensed Datanode. |
Dfs.replication |
Default: 3 |
Score for data replication |
Dfs.name.dir |
Example:/home/username/hadoop/namenode Default:/tmp |
When this value is a comma-delimited list of directories, the NameTable data will be copied to all directories for redundant backups. |
Dfs.data.dir |
Example:/home/username/hadoop/datanode Default:/tmp |
When this value is a comma-separated list of directories, the data will be stored in all directories, usually distributed on different devices. |
|
|
|
Mapred.system.dir |
Map/reduce the HDFS path to the framework storage system files. Like/hadoop/mapred/system/. |
This path is the path under the default file system (HDFS) and must be accessible from both the server and the client. |
Mapred.local.dir |
A comma-delimited list of paths under the local file system, where temporary data is stored map/reduce. |
Multipath helps take advantage of disk I/O. |
Mapred.tasktracker. {Map|reduce}.tasks.maximum |
The maximum number of map/reduce tasks that can be run on a tasktracker, and these tasks will run concurrently. |
The default is 2 (2 map and 2 reduce), which can be changed according to the hardware condition. |
Mapred.job.tracker |
The host (or IP) and port of the Jobtracker. |
Host: Port. |
Mapred.hosts/mapred.hosts.exclude |
License/Deny Tasktracker list. |
If necessary, use this file to control the list of licensed Tasktracker. |
|
|
|
Hadoop.job.history.user.location |
Default: Mapred.output.dir/_logs/history can also be set to none to deactivate |
History file record directory for the job |
Conf/slaves write the machine name or IP of all slave
Namenode Remember that each file is mapped into a blockid. Each blockid corresponding block is copied to a different machine.
The default block for Hadoop is 64MB
See if Namenode starts: http://localhost:50070/
See if Jobtracker starts: http://localhost:50030/
Reprint: http://eryk.iteye.com/blog/792962