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Posted to hdfs-issues@hadoop.apache.org by "hemanthboyina (JIRA)" <ji...@apache.org> on 2019/08/17 20:22:00 UTC
[jira] [Commented] (HDFS-14574) [distcp] Add ability to increase
the replication factor for fileList.seq
[ https://issues.apache.org/jira/browse/HDFS-14574?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16909821#comment-16909821 ]
hemanthboyina commented on HDFS-14574:
--------------------------------------
[~jojochuang] , In DIstCp we have preserve status (rbugpc..)
if we have an option for replication then these replications will override
any suggestions about this ?
> [distcp] Add ability to increase the replication factor for fileList.seq
> ------------------------------------------------------------------------
>
> Key: HDFS-14574
> URL: https://issues.apache.org/jira/browse/HDFS-14574
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: distcp
> Reporter: Wei-Chiu Chuang
> Assignee: hemanthboyina
> Priority: Major
>
> distcp creates fileList.seq with default replication factor = 3.
> For large clusters runing distcp job with thousands of mappers, that 3-replica for the file listing file is not good enough, because DataNodes easily run out of max number of xceivers.
>
> It looks like we can pass in a distcp option, update replication factor in when creating the sequence file writer: [https://github.com/apache/hadoop/blob/trunk/hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/SimpleCopyListing.java#L517-L521]
>
> Like this:
> {code:java}
> return SequenceFile.createWriter(getConf(),
> SequenceFile.Writer.file(pathToListFile),
> SequenceFile.Writer.keyClass(Text.class),
> SequenceFile.Writer.valueClass(CopyListingFileStatus.class),
> SequenceFile.Writer.compression(SequenceFile.CompressionType.NONE),
> SequenceFile.Writer.replication((short)100)); <-- this line
> {code}
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