[HDFS-15666] add average latency information to the SlowPeerReport

• Type: Improvement
• Status: Patch Available
• Priority: Minor
• Resolution: Unresolved
• Component/s: hdfs
• Assignee: Haibin Huang
• Reporter: Haibin Huang
• Created: 04/Nov/20 10:17
• Updated: 21/Jan/21 02:28

Description

In namenode's jmx, there is a SlowDisksReport like this:

[{"SlowDiskID":"dn3:disk1","Latencies":{"WRITE":1000.1}},{"SlowDiskID":"dn2:disk2","Latencies":{"WRITE":1000.1}},{"SlowDiskID":"dn1:disk2","Latencies":{"READ":1000.3}},{"SlowDiskID":"dn1:disk1","Latencies":{"METADATA":1000.1,"READ":1000.8}}]

So we can know the disk io letency from this report.However, SlowPeersReport dosen't have average latency:

[{"SlowNode":"node4","ReportingNodes":["node1"]},{"SlowNode":"node2","ReportingNodes":["node1","node3"]},{"SlowNode":"node1","ReportingNodes":["node2"]}]

I think we should add the average latency to the report, which can get from org.apache.hadoop.hdfs.server.protocol.SlowPeerReports#slowPeers.

After adding the average latency, the SlowPeerReport can be like this:

[{"SlowNode":"node4","ReportingNodes":[{"nodeId":"node1","averageLatency":2000.0}]},{"SlowNode":"node2","ReportingNodes":[{"nodeId":"node1","averageLatency":2000.0},{"nodeId":"node3","averageLatency":1000.0}]},{"SlowNode":"node1","ReportingNodes":[{"nodeId":"node2","averageLatency":2000.0}]}]