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https://issues.apache.org/jira/browse/HDFS-8418?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14549658#comment-14549658
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Jing Zhao commented on HDFS-8418:
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bq. INodeFile#getPreferredBlockReplication is method of INodeFile, not method
of BlockInfo
Ahh, actually you're right. We do not need to and also cannot put the same
logic into getPreferredBlockReplication. +1 for the current patch. I will
commit it shortly.
> Fix the isNeededReplication calculation for Striped block in NN
> ---------------------------------------------------------------
>
> Key: HDFS-8418
> URL: https://issues.apache.org/jira/browse/HDFS-8418
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Yi Liu
> Assignee: Yi Liu
> Priority: Critical
> Attachments: HDFS-8418-HDFS-7285.001.patch
>
>
> Currently when calculating {{isNeededReplication}} for striped block, we use
> BlockCollection#getPreferredBlockReplication to get expected replica number
> for striped block. See an example:
> {code}
> public void checkReplication(BlockCollection bc) {
> final short expected = bc.getPreferredBlockReplication();
> for (BlockInfo block : bc.getBlocks()) {
> final NumberReplicas n = countNodes(block);
> if (isNeededReplication(block, expected, n.liveReplicas())) {
> neededReplications.add(block, n.liveReplicas(),
> n.decommissionedAndDecommissioning(), expected);
> } else if (n.liveReplicas() > expected) {
> processOverReplicatedBlock(block, expected, null, null);
> }
> }
> }
> {code}
> But actually it's not correct, for example, if the length of striped file is
> less than a cell, then the expected replica of the block should be {{1 +
> parityBlkNum}} instead of {{dataBlkNum + parityBlkNum}}.
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