[HBASE-15625] Make minimum values configurable and smaller

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Invalid
• Affects Version/s: 1.2.0
• Labels: beginner
• Assignee: Unassigned
• Reporter: Jean-Marc Spaggiari
• Created: 10/Apr/16 09:02
• Updated: 11/Jun/22 20:05
• Resolved: 11/Jun/22 20:05

Description

When we start a RS, we check HConstants.HBASE_CLUSTER_MINIMUM_MEMORY_THRESHOLD to make sure we always keep 20% of the heap for HBase (See below). In the past maximum heap size was about 20GB, which means 4GB for HBase.

Today, with huge heaps and GC1, 20% gives a lot to HBase. Like with 80GB heap, it gives 16GB, which I think it not required.

We need to make HBASE_CLUSTER_MINIMUM_MEMORY_THRESHOLD configurable and lower it's default value to 10%. It will not make any difference on any HBase configuration but will allow admins to be more flexible.

Same thing for the minimum memstore and blockcache sizes.