Re: namenode migration

Thanks friends .Thanks a lot On Wed, Sep 26, 2012 at 11:52 PM, Robert Molina rmol...@hortonworks.comwrote: Here's another link that may help: http://wiki.apache.org/hadoop/NameNodeFailover On Wed, Sep 26, 2012 at 11:14 AM, Serge Blazhiyevskyy serge.blazhiyevs...@nice.com wrote:

Re: Detect when file is not being written by another process

AFAIK there is not way to determine i a file has been fully written or not. Oozie uses a feature of Hadoop which writes a _SUCCESS flag file in the output directory of a job. This _SUCCESS file is written at job completion time, thus ensuring all the output of the job is ready. This means that

Re: DFSClient may read wrong data in local read

Hi Colin， thanks for your reply. Where can I see the new design for BlockReaderLocal class? Thanks, LiuLei 2012/9/28 Colin McCabe cmcc...@alumni.cmu.edu We don't make very strong guarantees about what happens when clients read from a deleted file. DFSClients definitely may read data from

Re: Can we write output directly to HDFS from Mapper

Anand, You may read this in the FAQ: http://wiki.apache.org/hadoop/FAQ#Can_I_write_create.2BAC8-write-to_hdfs_files_directly_from_map.2BAC8-reduce_tasks.3F On Fri, Sep 28, 2012 at 9:45 AM, Balaraman, Anand anand_balara...@syntelinc.com wrote: Hi In Map-Reduce, is it appropriate to write the

Re: Can we write output directly to HDFS from Mapper

Can certainly do that. Indeed, if you set the number of reducers to 0, the map output will be directly written to HDFS by the framework itself. You may also want to look at http://hadoop.apache.org/docs/stable/mapred_tutorial.html#Task+Side-Effect+Files to see some things that need to be taken