On Mar 3, 2011, at 2:41 PM, Suresh Srinivas wrote:
> We have started pushing changes for namenode federation in to the feature
> branch HDFS-1052. The work items are created as subtask of the jira HDFS-1052
> and are based on the design document published in the same jira. By the end
> of this week, we will complete pushing the changes to HDFS-1052 branch.
> Though the changes in these jiras are already committed, please do provide
> your feedback on either HDFS-1052 or its subtasks. New items that come out of
> the feedback will be addressed in new jiras.
>
> Current status of the development:
> # The testing of this feature is underway. Most of the basic functionality
> has been tested both for a single namenode cluster (for backward
> compatibility) and with multiple namenodes.
> # All the existing tests and newly added tests pass (same as trunk).
>
> We plan on merging this branch to trunk after a week or two. This will help
> us continue make future changes on the trunk. I will send an announcement
> before merging the federation branch into trunk.
>
It sounds like merging into trunk is extremely premature. That said,
I'm still trying to understand the why's around this.
To me, this series of changes looks like it is going to make running a
grid much much harder for very little benefit. In particular, I don't see the
difference between running multiple NN/DN combinations verses running
federation, especially with client side mount tables in play.
