[HBASE-26311] Balancer gets stuck in cohosted replica distribution

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.5.0, 3.0.0-alpha-2, 2.4.9
• Component/s: Balancer
• Hadoop Flags: Reviewed
• Assignee: Clara Xiong
• Reporter: Clara Xiong
• Created: 30/Sep/21 05:26
• Updated: 11/Nov/21 02:02
• Resolved: 11/Nov/21 02:02

Description

In production, we found a corner case where balancer cannot make progress when there is cohosted replica. This is repro'ed on master branch using test added in HBASE-26310.

 

Issue Links

• is a child of: HBASE-25697 StochasticBalancer improvement for large scale clusters
• is related to: HBASE-26309 Balancer tends to move regions to the server at the end of list
• links to: Balancer Issues On an HBase Cluster on Cloud
• links to: GitHub Pull Request #3724
• links to: GitHub Pull Request #3804
• links to: GitHub Pull Request #3805

Sub-Tasks

• Replicas cohosted on a rack shouldn't keep triggering Balancer: Resolved
• Sum of multiplier of cost functions is not populated properly when we have a shortcut for trigger: Resolved