[HBASE-3799] Provide more accurate check for super underloaded region server in load balancer

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Later
• Affects Version/s: 0.90.2
• Component/s: mapreduce
• Assignee: Unassigned
• Reporter: Ted Yu
• Created: 18/Apr/11 23:29
• Updated: 12/Jun/22 18:30
• Resolved: 13/Sep/12 22:15

Description

HBASE-3609 used simple check for region server which recently joined the cluster so that both young and old regions from other region servers are assigned to it.
The check was too strict.
1 or more region may be assigned to this server before load balancer performs rebalancing.
The next time balancer runs, it wouldn't treat this server as seriously underloaded correctly and assign a lot of young regions to it.

We can use threshold over the number of regions to avoid such issue.

Issue Links

• is related to: HBASE-3724 Load balancer improvements