hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "maobaolong (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-8131) Implement a space balanced block placement policy
Date Fri, 28 Apr 2017 10:00:08 GMT

    [ https://issues.apache.org/jira/browse/HDFS-8131?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15988564#comment-15988564

maobaolong commented on HDFS-8131:

Hello, Thanks for this great improvement! 
What is the situation when this key is set between 0.5 and 1.0, i think it is better to set
to 1.0 always, Is that true? There must be something i don't understand well, Please point
it, thank you advance.

> Implement a space balanced block placement policy
> -------------------------------------------------
>                 Key: HDFS-8131
>                 URL: https://issues.apache.org/jira/browse/HDFS-8131
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: namenode
>    Affects Versions: 3.0.0-alpha1
>            Reporter: Liu Shaohui
>            Assignee: Liu Shaohui
>            Priority: Minor
>              Labels: BlockPlacementPolicy
>             Fix For: 2.8.0, 3.0.0-alpha1
>         Attachments: balanced.png, HDFS-8131.004.patch, HDFS-8131.005.patch, HDFS-8131.006.patch,
HDFS-8131-v1.diff, HDFS-8131-v2.diff, HDFS-8131-v3.diff
> The default block placement policy will choose datanodes for new blocks randomly, which
will result in unbalanced space used percent among datanodes after an cluster expansion. The
old datanodes always are in high used percent of space and new added ones are in low percent.
> Through we can used the external balance tool to balance the space used rate, it will
cost extra network IO and it's not easy to control the balance speed.
> An easy solution is to implement an balanced block placement policy which will choose
low used percent datanodes for new blocks with a little high possibility. In a not long term,
the used percent of datanodes will trend to be balanced.
> Suggestions and discussions are welcomed. Thanks

This message was sent by Atlassian JIRA

To unsubscribe, e-mail: hdfs-issues-unsubscribe@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-help@hadoop.apache.org

View raw message