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https://issues.apache.org/jira/browse/MAPREDUCE-1648?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12859296#action_12859296
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Vinod K V commented on MAPREDUCE-1648:
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Guilin, I opened MAPREDUCE-1648 as a sub-task for MAPREDUCE-1100. Given some 
uncertainities with your patch w.r.t performance and pipes, I am using 
MAPREDUCE-1648 as an incremental imporovement over what we have at present for 
task logs to address the pressing concern of excessive logging. Please comment 
if you wish or raise any objections there. Thanks!

> Use rolling to limit tasklogs
> -----------------------------
>
>                 Key: MAPREDUCE-1648
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-1648
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: tasktracker
>            Reporter: Guilin Sun
>            Priority: Minor
>         Attachments: syslog.patch
>
>
> There are at least two types of task-logs: syslog and stdlog
> Task-Jvm outputs syslog by log4j with TaskLogAppender, TaskLogAppender looks 
> just like "tail -c", it stores last N byte/line logs in memory(via queue), 
> and do real output only if all logs is commit and Appender is going to close.
> The common problem of TaskLogAppender and 'tail -c'  is keep everything in 
> memory and user can't see any log output while task is in progress.
> So I'm going to try RollingFileAppender  instead of  TaskLogAppender, use 
> MaxFileSize&MaxBackupIndex to limit log file size.
> RollingFileAppender is also suitable for stdout/stderr, just redirect 
> stdout/stderr to log4j via LoggingOutputStream, no client code have to be 
> changed, and RollingFileAppender seems better than 'tail -c' too.

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