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https://issues.apache.org/jira/browse/HDFS-8833?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14717142#comment-14717142
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Zhe Zhang commented on HDFS-8833:
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Thanks for the comment Kai. Great to know that the branch is working reliably.
Although the size of the patch is large, most of it is refactoring (changing
CLI, RPC etc.). There are only a few non-trivial changes as [summarized |
https://issues.apache.org/jira/browse/HDFS-8833?focusedCommentId=14700453&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14700453]
above.
I think it's worthwhile to finalize the *semantics* of using EC while it's
still in a feature branch. This change also affects the fsimage format (whether
ECPolicy ID is stored per file), which we should also finalize before merging
to trunk.
> Erasure coding: store EC schema and cell size in INodeFile and eliminate
> notion of EC zones
> -------------------------------------------------------------------------------------------
>
> Key: HDFS-8833
> URL: https://issues.apache.org/jira/browse/HDFS-8833
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Affects Versions: HDFS-7285
> Reporter: Zhe Zhang
> Assignee: Zhe Zhang
> Attachments: HDFS-8833-HDFS-7285-merge.00.patch,
> HDFS-8833-HDFS-7285-merge.01.patch, HDFS-8833-HDFS-7285.02.patch
>
>
> We have [discussed |
> https://issues.apache.org/jira/browse/HDFS-7285?focusedCommentId=14357754&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14357754]
> storing EC schema with files instead of EC zones and recently revisited the
> discussion under HDFS-8059.
> As a recap, the _zone_ concept has severe limitations including renaming and
> nested configuration. Those limitations are valid in encryption for security
> reasons and it doesn't make sense to carry them over in EC.
> This JIRA aims to store EC schema and cell size on {{INodeFile}} level. For
> simplicity, we should first implement it as an xattr and consider memory
> optimizations (such as moving it to file header) as a follow-on. We should
> also disable changing EC policy on a non-empty file / dir in the first phase.
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