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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "FAQ" by GautamGopalakrishnan
Date Sat, 25 Jul 2015 09:43:44 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "FAQ" page has been changed by GautamGopalakrishnan:
https://wiki.apache.org/hadoop/FAQ?action=diff&rev1=113&rev2=114

  == What does the message "Operation category READ/WRITE is not supported in state standby"
mean? ==
  In an HA-enabled cluster, DFS clients cannot know in advance which namenode is active at
a given time. So when a client contacts a namenode and it happens to be the standby, the READ
or WRITE operation will be refused and this message is logged. The client will then automatically
contact the other namenode and try the operation again. As long as there is one active and
one standby namenode in the cluster, this message can be safely ignored.
  
- If an application is configured to contact only one namenode always, this message indicates
that the application is failing to perform any read/write operation. In such situations, the
application would need to be modified to contact the other namenode.
+ If an application is configured to contact only one namenode always, this message indicates
that the application is failing to perform any read/write operation. In such situations, the
application would need to be modified to use the HA configuration for the cluster.
  
  = Platform Specific =
  == General ==

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