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Xiaolin Ha commented on HBASE-25768: ------------------------------------ Hi, [~kingWang] , the patch is for branch-2.4+. If you want to apply this patch for 2.1.0, most improvements since 2.1.0 is not required here. The main changes here are the chosen cost functions. You can try to back port it if you have interest. Thanks. > Support an overall coarse and fast balance strategy for StochasticLoadBalancer > ------------------------------------------------------------------------------ > > Key: HBASE-25768 > URL: https://issues.apache.org/jira/browse/HBASE-25768 > Project: HBase > Issue Type: Improvement > Components: Balancer > Affects Versions: 3.0.0-alpha-1, 2.0.0, 1.4.13 > Reporter: Xiaolin Ha > Assignee: Xiaolin Ha > Priority: Major > > When we use StochasticLoadBalancer + balanceByTable, we could face two > difficulties. > # For each table, their regions are distributed uniformly, but for the > overall cluster, still exiting imbalance between RSes; > # When there are large-scaled restart of RSes, or expansion for groups or > cluster, we hope the balancer can execute as soon as possible, but the > StochasticLoadBalancer may need a lot of time to compute costs. > We can detect these circumstances in StochasticLoadBalancer(such as using the > percentage of skew tables), and before the normal balance steps trying, we > can add a strategy to let it just balance like the SimpleLoadBalancer or use > few light cost functions here. > > -- This message was sent by Atlassian Jira (v8.20.7#820007)