[HBASE-25768] Support an overall coarse and fast balance strategy for StochasticLoadBalancer

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.0.0-alpha-1, 2.0.0, 1.4.13
• Fix Version/s: 3.0.0-beta-2
• Component/s: Balancer
• Assignee: Xiaolin Ha
• Reporter: Xiaolin Ha
• Created: 12/Apr/21 06:58
• Updated: 13/Jan/24 19:36

Description

When we use StochasticLoadBalancer + balanceByTable, we could face two difficulties.

1. For each table, their regions are distributed uniformly, but for the overall cluster, still exiting imbalance between RSes;
2. 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.

 

 

Issue Links

• links to: Design doc
• links to: GitHub Pull Request #4258