[jira] [Commented] (CASSANDRA-11100) nodetool command to rebalance the cluster in 3.0+

["Brandon Williams (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-11100?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15125103#comment-15125103 ] 

Brandon Williams commented on CASSANDRA-11100:
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See CASSANDRA-7601 for the pitfalls here to understand why we don't already have this.

> nodetool command to rebalance the cluster in 3.0+
> -------------------------------------------------
>
>                 Key: CASSANDRA-11100
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-11100
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Tools
>            Reporter: Wei Deng
>
> This is a follow-up JIRA to CASSANDRA-7032. At the end of that JIRA, [~benedict] proposed to add a nodetool command to rebalance the cluster through gradual application of the vnode token allocation algorithm introduced in that JIRA to more nodes.
> The limitation of current vnode allocation in C* 3.0 (post #7032) is that once the token allocation is already unbalanced in the cluster, it is not quite easy to rebalance without adding more nodes (so that they can take away the tokens from the over-utilized nodes), and adding nodes also won't help those under-utilized nodes. We need to give DBAs some tool to perform the balance operation in the whole cluster without adding nodes.
> Benedict also suggested to "introduce a modification to the #7032 algorithm for evaluating token removal, so that we could reduce the number of vnodes in an existing cluster, adding just the necessary number to get a good result", which could serve as the next phase of this work.



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