hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Todd Lipcon (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-2825) Add config option to turn off the writer preferring its local DN
Date Mon, 23 Jan 2012 18:28:40 GMT

    [ https://issues.apache.org/jira/browse/HDFS-2825?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13191321#comment-13191321
] 

Todd Lipcon commented on HDFS-2825:
-----------------------------------

This still reuses 99% of the code from the existing policy -- it places the first replica
rack-local and the other two on a separate (but same) rack. It still takes into account load
as well as disk space on all the nodes.

The primary purpose is for unit tests - see HDFS-2826 for example. It is not meant for general
purpose use by users, though as noted in the description there is potentially a use case.

Adding an entirely new block placement implementation for this purpose is overkill, since
it will duplicate all of the code from the existing one.
                
> Add config option to turn off the writer preferring its local DN
> ----------------------------------------------------------------
>
>                 Key: HDFS-2825
>                 URL: https://issues.apache.org/jira/browse/HDFS-2825
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: name-node
>    Affects Versions: 0.23.0
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>            Priority: Minor
>         Attachments: hdfs-2825.txt
>
>
> Currently, the default block placement policy always places the first replica in the
pipeline on the local node if there is a valid DN running there. In some network designs,
within-rack bandwidth is never constrained so this doesn't give much of an advantage. It would
also be really useful to disable this for MiniDFSCluster tests, since currently if you start
a multi-DN cluster and write with replication level 1, all of the replicas go to the same
DN.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message