[jira] [Commented] (HDFS-3702) Add an option for NOT writing the blocks locally if there is a datanode on the same box as the client

["Devaraj Das (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HDFS-3702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13720884#comment-13720884 ] 

Devaraj Das commented on HDFS-3702:
-----------------------------------

A workaround for this in the current codebase is to use the favored node API (HDFS-2576). For example, we could choose some node on the same rack as the first replica in the list of hosts passed to the create API.
                
> 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: 1.0.3, 2.0.0-alpha
>            Reporter: Nicolas Liochon
>            Priority: Minor
>
> 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.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira