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https://issues.apache.org/jira/browse/HDFS-7337?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14379823#comment-14379823
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Kai Zheng commented on HDFS-7337:
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As inspired with discussion in HDFS-7344 with [~szetszwo], a codec understands
and should give hints to NN how erased block(s) to be scheduled in priority for
recovering. For example, in RS(6,3), 1 erased block is not so urgent than 2 or
3 erased blocks. Will update the patch in HADOOP-11645 to reflect this thinking.
> Configurable and pluggable Erasure Codec and schema
> ---------------------------------------------------
>
> Key: HDFS-7337
> URL: https://issues.apache.org/jira/browse/HDFS-7337
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Zhe Zhang
> Assignee: Kai Zheng
> Attachments: HDFS-7337-prototype-v1.patch,
> HDFS-7337-prototype-v2.zip, HDFS-7337-prototype-v3.zip,
> PluggableErasureCodec-v2.pdf, PluggableErasureCodec.pdf
>
>
> According to HDFS-7285 and the design, this considers to support multiple
> Erasure Codecs via pluggable approach. It allows to define and configure
> multiple codec schemas with different coding algorithms and parameters. The
> resultant codec schemas can be utilized and specified via command tool for
> different file folders. While design and implement such pluggable framework,
> it’s also to implement a concrete codec by default (Reed Solomon) to prove
> the framework is useful and workable. Separate JIRA could be opened for the
> RS codec implementation.
> Note HDFS-7353 will focus on the very low level codec API and implementation
> to make concrete vendor libraries transparent to the upper layer. This JIRA
> focuses on high level stuffs that interact with configuration, schema and etc.
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