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https://issues.apache.org/jira/browse/HDFS-10843?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15469153#comment-15469153
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Erik Krogen commented on HDFS-10843:
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After further consideration it seems that it is probably most appropriate to
continue to use the preferred block size as the cached size until the block is
actually completed rather than just committed. This is more consistent with how
the rest of the code treats the under construction size (see comments on
{{INodeFile.{storagespaceConsumed,computeFileSize}}},
{{FileWithSnapshotFeature.updateQuotaAndCollectBlocks}},
{{FSDirAppendOp.computeQuotaDeltaForUCBlock}}); it seems that generally the
under construction / not under construction distinction is used rather than
committed vs. uncommitted.
> Quota Feature Cached Size != Computed Size When Block Committed But Not
> Completed
> ---------------------------------------------------------------------------------
>
> Key: HDFS-10843
> URL: https://issues.apache.org/jira/browse/HDFS-10843
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: hdfs, namenode
> Affects Versions: 2.6.0
> Reporter: Erik Krogen
> Assignee: Erik Krogen
>
> Currently when a block has been committed but has not yet been completed, the
> cached size (used for the quota feature) of the directory containing that
> block differs from the computed size. This results in log messages of the
> following form:
> bq. ERROR namenode.NameNode
> (DirectoryWithQuotaFeature.java:checkStoragespace(141)) - BUG: Inconsistent
> storagespace for directory /TestQuotaUpdate. Cached = 512 != Computed = 8192
> When a block is initially started under construction, the used space is
> conservatively set to a full block. When the block is committed, the cached
> size is updated to the final size of the block. However, the calculation of
> the computed size uses the full block size until the block is completed, so
> in the period where the block is committed but not completed they disagree.
> To fix this we need to decide which is correct and fix the other to match. It
> seems to me that the cached size is correct since once the block is committed
> its size will not change.
> This can be reproduced using the following steps:
> - Create a directory with a quota
> - Start writing to a file within this directory
> - Prevent all datanodes to which the file is written from communicating the
> corresponding BlockReceivedAndDeletedRequestProto to the NN temporarily (i.e.
> simulate a transient network partition/delay)
> - During this time, call DistributedFileSystem.getContentSummary() on the
> directory with the quota
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