[
https://issues.apache.org/jira/browse/HDFS-1073?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13031268#comment-13031268
]
Sanjay Radia commented on HDFS-1073:
------------------------------------
Todd, very good document; the effort you have put in clearly shows.
It will serve as design doc for this very critical part of the NN.
I have a few minor suggestions to improve the document.
* Add motivation section (this jira has most of the stuff you need). I would
include the following
** Decouple the image and edits file naming to reduce code complexity when a
new checkpoint is added
** Allow for secondary and backup NN to generate a checkpoint without
coordinating with NN.
** Allow for NN to trigger the checkpoint rather then the secondary/backup
** Allow one to implement an offline checkpointer
* Mention somewhere that we need to add NN shutdown command. Show that your
design can accommodate it. I would prefer that
in the case of shutdown, no edits log file is created and hence we could have
the option of not worrying about changes in edits opcodes during upgrade (see
the discussion on HDFS-1822)
* Section 4.4 - "group" you really mean "the edits across all dirs" - clarify.
4.5 - "Open question - upgrade when there wasn't a clean shutdown" -- INMHO No
we do not need to support it. I prefer
that there should be a clean shutdown (see my comment about) - not just save
namespace.
I will comment separately on the test cases.
> Simpler model for Namenode's fs Image and edit Logs
> ----------------------------------------------------
>
> Key: HDFS-1073
> URL: https://issues.apache.org/jira/browse/HDFS-1073
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Sanjay Radia
> Assignee: Todd Lipcon
> Attachments: hdfs-1073-editloading-algos.txt, hdfs-1073.txt,
> hdfs1073.pdf, hdfs1073.pdf, hdfs1073.pdf, hdfs1073.tex
>
>
> The naming and handling of NN's fsImage and edit logs can be significantly
> improved resulting simpler and more robust code.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
