hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "James Thomas (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-6800) Determine how Datanode layout changes should interact with rolling upgrade
Date Fri, 22 Aug 2014 22:06:12 GMT

    [ https://issues.apache.org/jira/browse/HDFS-6800?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14107594#comment-14107594
] 

James Thomas commented on HDFS-6800:
------------------------------------

Right, that's what I figured. Will talk to [~cmccabe] about his comments and post an updated
patch hopefully today, but in any case the changes should be minor and won't affect the overall
direction of the patch. Thanks again for your help.

> Determine how Datanode layout changes should interact with rolling upgrade
> --------------------------------------------------------------------------
>
>                 Key: HDFS-6800
>                 URL: https://issues.apache.org/jira/browse/HDFS-6800
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: datanode
>    Affects Versions: 2.6.0
>            Reporter: Colin Patrick McCabe
>            Assignee: James Thomas
>         Attachments: HDFS-6800.2.patch, HDFS-6800.3.patch, HDFS-6800.4.patch, HDFS-6800.patch
>
>
> We need to handle attempts to rolling-upgrade the DataNode to a new storage directory
layout.
> One approach is to disallow such upgrades.  If we choose this approach, we should make
sure that the system administrator gets a helpful error message and a clean failure when trying
to use rolling upgrade to a version that doesn't support it.  Based on the compatibility guarantees
described in HDFS-5535, this would mean that *any* future DataNode layout changes would require
a major version upgrade.
> Another approach would be to support rolling upgrade from an old DN storage layout to
a new layout.  This approach requires us to change our documentation to explain to users that
they should supply the {{\-rollback}} command on the command-line when re-starting the DataNodes
during rolling rollback.  Currently the documentation just says to restart the DataNode normally.
> Another issue here is that the DataNode's usage message describes rollback options that
no longer exist.  The help text says that the DN supports {{\-rollingupgrade rollback}}, but
this option was removed by HDFS-6005.



--
This message was sent by Atlassian JIRA
(v6.2#6252)

Mime
View raw message