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Posted to hdfs-issues@hadoop.apache.org by "Brahma Reddy Battula (JIRA)" <ji...@apache.org> on 2017/08/29 15:01:01 UTC
[jira] [Comment Edited] (HDFS-12136) BlockSender performance
regression due to volume scanner edge case
[ https://issues.apache.org/jira/browse/HDFS-12136?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16145433#comment-16145433 ]
Brahma Reddy Battula edited comment on HDFS-12136 at 8/29/17 3:00 PM:
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bq.so we could target 2.8.3 for the fix.
updated {{2.8.3}} as target version.
was (Author: brahmareddy):
bq.so we could target 2.8.3 for the fix.
updated as target version.
> BlockSender performance regression due to volume scanner edge case
> ------------------------------------------------------------------
>
> Key: HDFS-12136
> URL: https://issues.apache.org/jira/browse/HDFS-12136
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: datanode
> Affects Versions: 2.8.0
> Reporter: Daryn Sharp
> Assignee: Daryn Sharp
> Priority: Critical
> Attachments: HDFS-12136.branch-2.patch, HDFS-12136.trunk.patch
>
>
> HDFS-11160 attempted to fix a volume scan race for a file appended mid-scan by reading the last checksum of finalized blocks within the {{BlockSender}} ctor. Unfortunately it's holding the exclusive dataset lock to open and read the metafile multiple times Block sender instantiation becomes serialized.
> Performance completely collapses under heavy disk i/o utilization or high xceiver activity. Ex. lost node replication, balancing, or decommissioning. The xceiver threads congest creating block senders and impair the heartbeat processing that is contending for the same lock. Combined with other lock contention issues, pipelines break and nodes sporadically go dead.
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