Re: [VOTE] Merge HDFS-6581 to trunk - Writing to replicas in memory.

[Arpit Agarwal <aa...@hortonworks.com>]

The HDFS-6581 branch has been merged into trunk.


On Tue, Sep 30, 2014 at 2:30 PM, Arpit Agarwal <aa...@hortonworks.com>
wrote:

> HDFS Devs,
>
> The vote passes with 4 +1s (Jitendra, Jing, Suresh and mine), two -0s and
> no binding vetoes. The branch will be merged to trunk by tomorrow.
>
> Thank you to everyone who voted and provided feedback. The changes will be
> merged to branch-2 when we have a resolution for the merge blocker raised
> by Colin. This will also let the changes bake in trunk for a few days.
>
> Regards,
> Arpit
>
>
> On Mon, Sep 22, 2014 at 5:24 PM, Arpit Agarwal <aa...@hortonworks.com>
> wrote:
>
>> HDFS Devs,
>>
>> We propose merging the HDFS-6581 development branch to trunk.
>>
>> The work adds support to write to HDFS blocks in memory. The target use
>> case covers applications writing relatively small, intermediate data sets
>> with low latency. We introduce a new CreateFlag for the existing CreateFile
>> API. HDFS will subsequently attempt to place replicas of file blocks in
>> local memory with disk writes occurring off the hot path. The current
>> design is a simplification of original ideas from Sanjay Radia on HDFS-5851.
>>
>> Key goals of the feature were minimal API changes to reduce application
>> burden and best effort data durability. The feature is optional and
>> requires appropriate DN configuration from administrators.
>>
>> Design doc:
>>
>> https://issues.apache.org/jira/secure/attachment/12661926/HDFSWriteableReplicasInMemory.pdf
>>
>> Test plan:
>>
>> https://issues.apache.org/jira/secure/attachment/12669452/Test-Plan-for-HDFS-6581-Memory-Storage.pdf
>>
>> There are 28 resolved sub-tasks under HDFS-6581, 3 open tasks for
>> tests+Jenkins issues  and 7 open subtasks tracking planned improvements.
>> The latest merge patch is 3300 lines of changed code of which 1300 lines is
>> new and updated tests. Merging the branch to trunk will allow HDFS
>> applications to start evaluating the feature. We will continue work on
>> documentation, performance tuning and metrics in parallel with the vote and
>> post-merge.
>>
>> Contributors to design and code include Xiaoyu Yao, Sanjay Radia,
>> Jitendra Pandey, Tassapol Athiapinya, Gopal V, Bikas Saha, Vikram Dixit,
>> Suresh Srinivas and Chris Nauroth.
>>
>> Thanks to Haohui Mai, Colin Patrick McCabe, Andrew Wang, Todd Lipcon,
>> Eric Baldeschwieler and Vinayakumar B for providing useful feedback on
>> HDFS-6581, HDFS-5851 and sub-tasks.
>>
>> The vote runs for the usual 7 days and will expire at 12am PDT on Sep 30.
>> Here is my +1 for the merge.
>>
>> Regards,
>> Arpit
>>
>
>

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