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https://issues.apache.org/jira/browse/HBASE-13965?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14610601#comment-14610601
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Lei Chen commented on HBASE-13965:
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I agree that the unused balancers should be purged or made into attributes of
the stochastic load balancer. I think it may be better to do it in another
Jira, since “One thing at a time”.
About the ever growing map, I’m thinking of two ways to solve this problem.
1. Besides updateStochasticCost, add another method (or add a boolean
parameter) which should be called when the table is deleted. This will allow
the map to contain only existing tables
2. Use a fixed-size most recent used (MRU) cache to store the map. The
size can be configurable.
Any suggestion?
> Stochastic Load Balancer JMX Metrics
> ------------------------------------
>
> Key: HBASE-13965
> URL: https://issues.apache.org/jira/browse/HBASE-13965
> Project: HBase
> Issue Type: Improvement
> Components: Balancer, metrics
> Reporter: Lei Chen
> Assignee: Lei Chen
> Attachments: HBase-13965-v1.patch,
> stochasticloadbalancerclasses_v2.png
>
>
> Today’s default HBase load balancer (the Stochastic load balancer) is cost
> function based. The cost function weights are tunable but no visibility into
> those cost function results is directly provided.
> A driving example is a cluster we have been tuning which has skewed rack size
> (one rack has half the nodes of the other few racks). We are tuning the
> cluster for uniform response time from all region servers with the ability to
> tolerate a rack failure. Balancing LocalityCost, RegionReplicaRack Cost and
> RegionCountSkew Cost is difficult without a way to attribute each cost
> function’s contribution to overall cost.
> What this jira proposes is to provide visibility via JMX into each cost
> function of the stochastic load balancer, as well as the overall cost of the
> balancing plan.
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