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https://issues.apache.org/jira/browse/HDFS-6658?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Daryn Sharp updated HDFS-6658:
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Attachment: HDFS-6658.patch
Sorry, last minute change to revert code back to as close as possible to
current code busted the repl monitor with NPE.
Based on preconditions I've added, they are detecting some bugs in the BM that
are currently masked. Namely the BM is designed to return phony values for
blocks not in the blocks map, ie. 0 counts, 0 storages, etc - instead of the
caller dealing with the situation. Added log to getStorages when iterating a
non-existent block.
> Namenode memory optimization - Block replicas list
> ---------------------------------------------------
>
> Key: HDFS-6658
> URL: https://issues.apache.org/jira/browse/HDFS-6658
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: namenode
> Affects Versions: 2.4.1
> Reporter: Amir Langer
> Assignee: Daryn Sharp
> Attachments: BlockListOptimizationComparison.xlsx, BlocksMap
> redesign.pdf, HDFS-6658.patch, HDFS-6658.patch, HDFS-6658.patch, Namenode
> Memory Optimizations - Block replicas list.docx
>
>
> Part of the memory consumed by every BlockInfo object in the Namenode is a
> linked list of block references for every DatanodeStorageInfo (called
> "triplets").
> We propose to change the way we store the list in memory.
> Using primitive integer indexes instead of object references will reduce the
> memory needed for every block replica (when compressed oops is disabled) and
> in our new design the list overhead will be per DatanodeStorageInfo and not
> per block replica.
> see attached design doc. for details and evaluation results.
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