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https://issues.apache.org/jira/browse/HDFS-8818?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14644620#comment-14644620
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Chang Li commented on HDFS-8818:
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[~szetszwo] thanks for the patch. One thing I am concerned is the change
{code}
- return srcBlocks.size() < SOURCE_BLOCKS_MIN_SIZE && blocksToReceive > 0;
+ return blocksToReceive > 0;
{code}
now that dispatcher will keep fetching more blocks from namenode every
iteration, but namenode is likely to return very same list of blocks since the
block moving is not that fast and namenode can't know the blocks just moved
instantly. This could increase useless load on namenode.
> Allow Balancer to run faster
> ----------------------------
>
> Key: HDFS-8818
> URL: https://issues.apache.org/jira/browse/HDFS-8818
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: balancer & mover
> Reporter: Tsz Wo Nicholas Sze
> Assignee: Tsz Wo Nicholas Sze
> Attachments: h8818_20150723.patch, h8818_20150727.patch
>
>
> The original design of Balancer is intentionally to make it run slowly so
> that the balancing activities won't affect the normal cluster activities and
> the running jobs.
> There are new use case that cluster admin may choose to balance the cluster
> when the cluster load is low, or in a maintain window. So that we should
> have an option to allow Balancer to run faster.
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