[
https://issues.apache.org/jira/browse/HDFS-7116?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14552774#comment-14552774
]
Rakesh R commented on HDFS-7116:
--------------------------------
Hi [~ajisakaa], its really an interesting feature and would like to take this
ahead. To begin with, I have gone through the {{-setBalancerBandwidth}}
feature. Here, Namenode is sending the {{DNA_BALANCERBANDWIDTHUPDATE}} command
to the Datanodes as a heartbeat response and Datanode will update the new
bandwidth value. In normal case, after setting the bandwidth all the datanodes
will have the same value. But I could see few corner cases where all the
Datanodes in a cluster not having unique bandwidth value.
Case-1) Newly added Datanodes will not aware about the new value and will have
the default bandwidth value.
Case-2) Assume we have 10 Datanodes, after sending heartbeat responses to 1 to
5 Datanodes, unfortunately Namenode restarted. Since bandwidth value is not
persisted restarted Namenode will not have the new bandwidth value. Now, the
rest of the 6 to 10 Datanodes will be having old value.
Is this expected behavior?. If yes, we have to design the
{{-getBalancerBandwidth}} command in such a way to list each Datanode with the
corresponding bandwidth value like, {{each Datanode = bandwidth value}}. Any
thoughts?
> Add a command to get the bandwidth of balancer
> ----------------------------------------------
>
> Key: HDFS-7116
> URL: https://issues.apache.org/jira/browse/HDFS-7116
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: balancer & mover
> Reporter: Akira AJISAKA
>
> Now reading logs is the only way to check how the balancer bandwidth is set.
> It would be useful for administrators if they can get the parameter via CLI.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
