He Xiaoqiao created HDFS-14332:
----------------------------------
Summary: NetworkTopology#getWeightUsingNetworkLocation return
unexpected result
Key: HDFS-14332
URL: https://issues.apache.org/jira/browse/HDFS-14332
Project: Hadoop HDFS
Issue Type: Bug
Components: namenode
Reporter: He Xiaoqiao
Assignee: He Xiaoqiao
Consider the following scenario:
1. there are 4 slaves and topology like:
Rack: /IDC/RACK1
hostname1
hostname2
Rack: /IDC/RACK2
hostname3
hostname4
2. Reader from hostname1, and calculate weight between reader and [hostname1,
hostname3, hostname4] by #getWeight, and their corresponding values are [0,4,4]
3. Reader from client which is not in the topology, and in the same IDC but in
none rack of the topology, and calculate weight between reader and [hostname1,
hostname3, hostname4] by #getWeightUsingNetworkLocation, and their
corresponding values are [2,2,2]
4. Other different Reader can get the similar results.
The weight result for case #3 is obviously not the expected value, the truth is
[4,4,4]. this issue may cause reader not really following arrange: local ->
local rack -> remote rack.
After dig the detailed implement, the root cause is
#getWeightUsingNetworkLocation only calculate distance between Racks rather
than hosts.
I think we should add constant 2 to correct the weight of
#getWeightUsingNetworkLocation.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org
