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https://issues.apache.org/jira/browse/HDFS-9917?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15213947#comment-15213947
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Vinayakumar B commented on HDFS-9917:
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Current changes for clearing IBRs on re-Register() looks good.
For the second part, i.e. Avoid accumulation of IBRs when the standby is down
for long time, can we consider as below. (Already mentioned in my above
comment)
1. IBRs for StandbyNN can have a threshold ( say 100K or 1Million IBRs ).
2. Also not to loose any important IBRs, IBRs can be cleared when "the
threshold is reached AND 'lastIBR' is more than 'heartbeatExpiryInterval'. i.e.
DataNode is considered dead in Namenode side". In that case, for sure
re-Register() will be called on reconnection to running NameNode (if any).
Only question is, *heartBeatExpiryInterval* in NameNode depends on conf
"dfs.namenode.heartbeat.recheck-interval" which is namenode side configuration.
By default this is 5 min. If there is any change in this in Namenode side, that
change should also be present in datanode config. Is it okay to use this? or
introduce a common conf to NN and DN?
[~szetszwo], what is your opinion in this?
> IBR accumulate more objects when SNN was down for sometime.
> -----------------------------------------------------------
>
> Key: HDFS-9917
> URL: https://issues.apache.org/jira/browse/HDFS-9917
> Project: Hadoop HDFS
> Issue Type: Bug
> Reporter: Brahma Reddy Battula
> Assignee: Brahma Reddy Battula
> Attachments: HDFS-9917.patch
>
>
> SNN was down for sometime because of some reasons..After restarting SNN,it
> became unreponsive because
> - 29 DN's sending IBR in each 5 million ( most of them are delete IBRs),
> where as each datanode had only ~2.5 million blocks.
> - GC can't trigger on this objects since all will be under RPC queue.
> To recover this( to clear this objects) ,restarted all the DN's one by
> one..This issue happened in 2.4.1 where split of blockreport was not
> available.
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