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courses:mapreduce-tutorial:step-9 [2012/01/25 16:16]
straka |
courses:mapreduce-tutorial:step-9 [2012/01/25 16:18]
straka |
| Every Hadoop option has a read-only default. These are overridden by cluster specific options. Lastly, all of these are overriden by job specific options given on the command line (or set using the Java API). | Every Hadoop option has a read-only default. These are overridden by cluster specific options. Lastly, all of these are overriden by job specific options given on the command line (or set using the Java API). |
| |
| ==== Mapping of Perl options to Hadoop ==== | ===== A brief list of Hadoop options ===== |
| ^ Perl options ^ Hadoop options ^ | |
| | no options \\ (running locally) | ''-Dmapred.job.tracker=local'' \\ ''-Dmapred.local.dir=hadoop-localrunner-tmp'' \\ ''-Dhadoop.tmp.dir=hadoop-localrunner-tmp'' | | |
| | ''-jt cluster_master'' | ''-Dmapred.job.tracker=cluster_master'' | | |
| | ''-c cluster_machines'' | configuration of new cluster contains \\ ''-Dmapred.job.tracker=cluster_master'' | | |
| | ''-r number_of_reducers'' | ''-Dmapred.reduce.tasks=number_of_reducers'' | | |
| | |
| ===== Brief list of Hadoop options ===== | |
| ^ Hadoop option ^ Default value ^ Description ^ | ^ Hadoop option ^ Default value ^ Description ^ |
| | ''mapred.job.tracker'' | ? | Cluster master | | | ''mapred.job.tracker'' | ? | Cluster master | |
| | ''mapred.reduce.tasks'' | 1 | Number of reducers | | | ''mapred.reduce.tasks'' | 1 | Number of reducers | |
| | ''mapred.min.split.size'' | 1 | Minimum size of file split in bytes | | | ''mapred.min.split.size'' | 1 | Minimum size of file split in bytes | |
| | ''mapred.max.split.size'' | 2^63-1 | Minimum size of file split in bytes | | | ''mapred.max.split.size'' | 2%%^%%63-1 | Minimum size of file split in bytes | |
| | ''mapred.map.tasks.speculative.execution'' | true | If true, then multiple instances of some map tasks may be executed in parallel | | | ''mapred.map.tasks.speculative.execution'' | true | If true, then multiple instances of some map tasks may be executed in parallel | |
| | ''mapred.reduce.tasks.speculative.execution'' | true | If true, then multiple instances of some reduce tasks may be executed in parallel | | | ''mapred.reduce.tasks.speculative.execution'' | true | If true, then multiple instances of some reduce tasks may be executed in parallel | |
| | ''mapred.compress.map.output'' | false | Should the outputs of the maps be compressed before being sent across the network. Uses SequenceFile compression | | | ''mapred.compress.map.output'' | false | Should the outputs of the maps be compressed before being sent across the network. Uses SequenceFile compression | |
| |
| A more complete list (but not exhaustive) can be found {{http://hadoop.apache.org/common/docs/r1.0.0/mapred-default.html|here}. | A more complete list (but not exhaustive) can be found [[http://hadoop.apache.org/common/docs/r1.0.0/mapred-default.html|here]]. |
| | |
| | ===== Mapping of Perl options to Hadoop ===== |
| | ^ Perl options ^ Hadoop options ^ |
| | | no options \\ (running locally) | ''-Dmapred.job.tracker=local'' \\ ''-Dmapred.local.dir=hadoop-localrunner-tmp'' \\ ''-Dhadoop.tmp.dir=hadoop-localrunner-tmp'' | |
| | | ''-jt cluster_master'' | ''-Dmapred.job.tracker=cluster_master'' | |
| | | ''-c cluster_machines'' | configuration of new cluster contains \\ ''-Dmapred.job.tracker=cluster_master'' | |
| | | ''-r number_of_reducers'' | ''-Dmapred.reduce.tasks=number_of_reducers'' | |
| |
