+1

I also thought that version mismatch is FB specific.
Other people will not be able to run different versions of NN and SNN.
--Konstantin

On 4/2/2010 10:41 AM, Todd Lipcon wrote:
On Fri, Apr 2, 2010 at 10:38 AM, Stack<st...@duboce.net>  wrote:

>  Please on committing HDFS-1024 to the hadoop 0.20 branch.
>
>  Background:
>
>  HDFS-1024 fixes possible trashing of fsimage because of failed copy
>  from 2NN and NN.  Ordinarily, possible corruption of this proportion
>  would merit commit w/o need of a vote only Dhruba correctly notes that
>  UNLESS both NN and 2NN are upgraded, HDFS-1024 becomes an incompatible
>  change (the NN<->2NN communication will fail always).  IMO, this
>  incompatible change can be plastered over with a release note; e.g.
>  WARNING, you MUST update NN and 2NN when you go to 0.20.3 hadoop.  If
>  you agree with me, please vote +1 on commit.
>
+1. If I recall correctly the NN and 2NN already do a very strict version
check in branch 20, so it's not any more incompatible than any other change.
(I think Dhruba made the version check less strict in the FB branch)

-Todd



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