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MapReduce, mail # user - temporary file locations for YARN applications


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RE: temporary file locations for YARN applications
John Lilley 2013-10-20, 20:35
Harsh, thanks for the quick response.  These files don't need to be on the DFS (although we use that too).  These are local files used during sorting, joining, transitive closure.  

The task-relative folder might be good enough, but our app *can* make use of multiple temp folders if they are available.  Our YARN app can be fairly I/O intensive; is it possible to allocate more than one temp folder on different physical devices?  

Or perhaps YARN might help us. Will YARN assign tasks to CWD folders on different disks so that they do not compete with each other on I/O?  

For that matter, where does MR allocate the temporary files generated by Mapper output?  Presumably MR has the same I/O parallelism requirements that we do.

Thanks
John
-----Original Message-----
From: Harsh J [mailto:[EMAIL PROTECTED]]
Sent: Sunday, October 20, 2013 10:49 AM
To: <[EMAIL PROTECTED]>
Subject: Re: temporary file locations for YARN applications

Every container gets its own local work directory (You can use the relative ./) thats auto-cleaned up at the end of the container's life.
This is the best place to store the temporary files. This is not something you need custom configuration for.

Do the files need to be on a distributed FS or a local one?

On Sun, Oct 20, 2013 at 8:54 PM, John Lilley <[EMAIL PROTECTED]> wrote:
> We have a pure YARN application (no MapReduce) that has need to store
> a significant amount of temporary data.  How can we know the best
> location for these files?  How can we ensure that our YARN tasks have
> write access to these locations?  Is this something that must be configured outside of YARN?
> Thanks,
> John

--
Harsh J