[HBASE-3373] Allow regions to be load-balanced by table

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.20.6
• Fix Version/s: 0.94.0
• Component/s: master
• Hadoop Flags: Reviewed

Release Note

There is a parameter, hbase.regions.slop, with default value of 0.2
This parameter allows actual region count to deviate by this percentage from (ideal) average region count.

• Assignee: Ted Yu
• Reporter: Ted Yu
• Created: 18/Dec/10 08:29
• Updated: 04/Dec/12 19:11
• Resolved: 18/Jan/12 18:10

Description

From our experience, cluster can be well balanced and yet, one table's regions may be badly concentrated on few region servers.
For example, one table has 839 regions (380 regions at time of table creation) out of which 202 are on one server.

It would be desirable for load balancer to distribute regions for specified tables evenly across the cluster. Each of such tables has number of regions many times the cluster size.

Issue Links

• is part of: HBASE-3724 Load balancer improvements
• is related to: HBASE-2480 Smarter load-balancing