[HDFS-14554] Avoid to process duplicate blockreport of datanode when namenode in startup safemode

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Implemented
• Component/s: namenode
• Assignee: Xiaoqiao He
• Reporter: Xiaoqiao He
• Created: 07/Jun/19 14:38
• Updated: 30/Sep/19 04:22
• Resolved: 09/Jun/19 17:14

Description

When NameNode restart and enter stage of startup safemode, load of NameNode could be very high since blockreport request storm from datanodes together. Sometimes datanode may request blockreport times because NameNode doesn't return in time and DataNode meet timeoutexception then retry, Thus it sharpens load of NameNode.
So we should check and filter duplicate blockreport request from one datannode and reduce load of Namenode.