No, only the "active" namenode sends commands back to the datanodes in avatar node setup.
On Aug 9, 2010, at 5:05 PM, André Oriani <ra078...@students.ic.unicamp.br> wrote: > Hi all, > > I was studying the code of HDFS-976 and Dhruba's overview about Avatar Nodes > ( > http://hadoopblog.blogspot.com/2010/02/hadoop-namenode-high-availability.html) > when some questions came to my mind. If I understood correctly, avatar > datanodes send heartbeats, block reports and block received messages to both > avatar namenodes. Does both avatar namenodes send DataCommands back ? If so, > how contradictory commands are avoided? What would be the impact of > forwarding messages to a third, fourth,... namenode ? > > Thanks and Regards, > André Oriani