[ https://issues.apache.org/jira/browse/HDFS-10966?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15685014#comment-15685014 ]
Kihwal Lee commented on HDFS-10966: ----------------------------------- Committed to branch-2.7. Thanks for working on this [~mwagner] and finishing it up, [~zhz]. > Enhance Dispatcher logic on deciding when to give up a source DataNode > ---------------------------------------------------------------------- > > Key: HDFS-10966 > URL: https://issues.apache.org/jira/browse/HDFS-10966 > Project: Hadoop HDFS > Issue Type: Bug > Components: balancer & mover > Reporter: Zhe Zhang > Assignee: Mark Wagner > Fix For: 2.7.4, 3.0.0-alpha2 > > Attachments: HDFS-10966-branch-2.7.00.patch, HDFS-10966.00.patch, > HDFS-10966.01.patch > > > When a {{Dispatcher}} thread works on a source DataNode, in each iteration it > tries to execute a {{PendingMove}}. If no block is moved after 5 iterations, > this source (over-utlized) DataNode is given up for this Balancer iteration > (20 mins). This is problematic if the source DataNode was heavily loaded in > the beginning of the iteration. It will quickly encounter 5 unsuccessful > moves and be abandoned. > We should enhance this logic by e.g. using elapsed time instead of number of > iterations. > {code} > // Check if the previous move was successful > } else { > // source node cannot find a pending block to move, iteration +1 > noPendingMoveIteration++; > // in case no blocks can be moved for source node's task, > // jump out of while-loop after 5 iterations. > if (noPendingMoveIteration >= MAX_NO_PENDING_MOVE_ITERATIONS) { > LOG.info("Failed to find a pending move " + > noPendingMoveIteration > + " times. Skipping " + this); > resetScheduledSize(); > } > } > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org