hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Edward Bortnikov (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-5453) Support fine grain locking in FSNamesystem
Date Mon, 23 Dec 2013 08:07:52 GMT

    [ https://issues.apache.org/jira/browse/HDFS-5453?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13855489#comment-13855489
] 

Edward Bortnikov commented on HDFS-5453:
----------------------------------------

Orthogonally to the recent thread ... Attached is a spreadsheet with simulation results that
exemplify the ballpark gain from transitioning to a completely lock-free architecture. It
is based on a very recent Hadoop 2.0 code. 

This is more of a long-term feature, which we believe is what the namenode ultimately needs.


> Support fine grain locking in FSNamesystem
> ------------------------------------------
>
>                 Key: HDFS-5453
>                 URL: https://issues.apache.org/jira/browse/HDFS-5453
>             Project: Hadoop HDFS
>          Issue Type: New Feature
>          Components: namenode
>    Affects Versions: 2.0.0-alpha, 3.0.0
>            Reporter: Daryn Sharp
>            Assignee: Daryn Sharp
>         Attachments: async_simulation.xlsx
>
>
> The namesystem currently uses a course grain lock to control access.  This prevents concurrent
writers in different branches of the tree, and prevents readers from accessing branches that
writers aren't using.
> Features that introduce latency to namesystem operations, such as cold storage of inodes,
will need fine grain locking to avoid degrading the entire namesystem's throughput.



--
This message was sent by Atlassian JIRA
(v6.1.5#6160)

Mime
View raw message