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https://issues.apache.org/jira/browse/HADOOP-11828?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14534051#comment-14534051
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jack liuquan commented on HADOOP-11828:
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Hi Kai,
I can't catch your meanings exactly.
The encoding/decoding of bytes in one chunk(one chunk is a sub-stripe) is
linear operation, but not linear between chunks in one block.
If we read bytes in blocks is a linear operation, and it's right that the
encoding/decoding of units should happen in aligned boundaries.
But if we can use an offset to read chunks parallel, I think we can
encoding/decoding bytes in flow mode, not need in aligned boundaries .
Do I answer your question? Thanks!
> Implement the Hitchhiker erasure coding algorithm
> -------------------------------------------------
>
> Key: HADOOP-11828
> URL: https://issues.apache.org/jira/browse/HADOOP-11828
> Project: Hadoop Common
> Issue Type: Sub-task
> Reporter: Zhe Zhang
> Assignee: jack liuquan
> Attachments: 7715-hitchhikerXOR-v2-testcode.patch,
> 7715-hitchhikerXOR-v2.patch, HADOOP-11828-hitchhikerXOR-V3.patch,
> HADOOP-11828-hitchhikerXOR-V4.patch, HDFS-7715-hhxor-decoder.patch,
> HDFS-7715-hhxor-encoder.patch
>
>
> [Hitchhiker |
> http://www.eecs.berkeley.edu/~nihar/publications/Hitchhiker_SIGCOMM14.pdf] is
> a new erasure coding algorithm developed as a research project at UC
> Berkeley. It has been shown to reduce network traffic and disk I/O by 25%-45%
> during data reconstruction. This JIRA aims to introduce Hitchhiker to the
> HDFS-EC framework, as one of the pluggable codec algorithms.
> The existing implementation is based on HDFS-RAID.
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