[HBASE-15504] Fix Balancer in 1.3 not moving regions off overloaded regionserver

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.3.0
• Fix Version/s: 1.3.0, 2.0.0
• Hadoop Flags: Reviewed
• Assignee: Elliott Neil Clark
• Reporter: Elliott Neil Clark
• Created: 21/Mar/16 18:50
• Updated: 09/Nov/17 00:40
• Resolved: 14/Apr/16 01:17

Description

We pushed 1.3 to a couple of clusters. In some cases the regions were assigned VERY un-evenly and the regions would not move after that.

We ended up with one rs getting thousands of regions and most servers getting 0. Running balancer would do nothing. The balancer would say that it couldn't find a solution with less than the current cost.