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https://issues.apache.org/jira/browse/HDFS-3702?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Lei (Eddy) Xu updated HDFS-3702:
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Attachment: HDFS-3702.002.patch
[~stack] and [~nkeywal] Thanks for your reviews. Your feedbacks help a lot!
I have updated the patch to:
# addressed comments and added logs.
# bq. Are there other cases in the codebase that you know of where the DN
NetUtils.getHostname() works as a key for finding the datanode info in the NN?
I changed it to use all local network interface IP addresses as keys to find
datanode.
# bq. we are doing an extra trip to the NN when we open a DFSOS with
AVOID_LOCAL_COPY set?
It now only asks NN when creating DFSClient, which is presumably a relatively
rare operation. [~stack] Could you help to verify this assumption? Thanks!
> Add an option for NOT writing the blocks locally if there is a datanode on
> the same box as the client
> -----------------------------------------------------------------------------------------------------
>
> Key: HDFS-3702
> URL: https://issues.apache.org/jira/browse/HDFS-3702
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs-client
> Affects Versions: 2.5.1
> Reporter: Nicolas Liochon
> Assignee: Lei (Eddy) Xu
> Priority: Minor
> Attachments: HDFS-3702.000.patch, HDFS-3702.001.patch,
> HDFS-3702.002.patch
>
>
> This is useful for Write-Ahead-Logs: these files are writen for recovery
> only, and are not read when there are no failures.
> Taking HBase as an example, these files will be read only if the process that
> wrote them (the 'HBase regionserver') dies. This will likely come from a
> hardware failure, hence the corresponding datanode will be dead as well. So
> we're writing 3 replicas, but in reality only 2 of them are really useful.
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