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https://issues.apache.org/jira/browse/HADOOP-3232?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Johan Oskarsson updated HADOOP-3232:
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Attachment: du-nonblocking-v5-trunk.patch
1. Changed
2. Removed the reference to DU and call DU.this.run() instead.
Scheduling it with an Executor would still have a running thread that keeps
track of the scheduling, no? ScheduledThreadPoolExecutor for example.
The other example was starting a thread inside getUsed() then returning the old
value while the DU runs? Wouldn't that cause problems where getUsed is called
very infrequently? Perhaps this is never an issue?
Anyway, I added the comment about improving this with a non permanent thread
anyway, in the most common case I guess that would work fine.
As mentioned this patch will cause one new findbugs error, starting a thread in
the constructor, hard to avoid without having a new method to start it,
breaking the public interface.
> Datanodes time out
> ------------------
>
> Key: HADOOP-3232
> URL: https://issues.apache.org/jira/browse/HADOOP-3232
> Project: Hadoop Core
> Issue Type: Bug
> Components: dfs
> Affects Versions: 0.16.2, 0.16.3, 0.16.4
> Environment: 10 node cluster + 1 namenode
> Reporter: Johan Oskarsson
> Priority: Critical
> Fix For: 0.18.0
>
> Attachments: du-nonblocking-v1.patch, du-nonblocking-v2-trunk.patch,
> du-nonblocking-v4-trunk.patch, du-nonblocking-v5-trunk.patch,
> hadoop-hadoop-datanode-new.log, hadoop-hadoop-datanode-new.out,
> hadoop-hadoop-datanode.out, hadoop-hadoop-namenode-master2.out
>
>
> I recently upgraded to 0.16.2 from 0.15.2 on our 10 node cluster.
> Unfortunately we're seeing datanode timeout issues. In previous versions
> we've often seen in the nn webui that one or two datanodes "last contact"
> goes from the usual 0-3 sec to ~200-300 before it drops down to 0 again.
> This causes mild discomfort but the big problems appear when all nodes do
> this at once, as happened a few times after the upgrade.
> It was suggested that this could be due to namenode garbage collection, but
> looking at the gc log output it doesn't seem to be the case.
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