Ajit, NameNode takes care of over-replication situations, and you needn't have to worry about over-replicated blocks or do anything manually.
On Wed, Aug 22, 2012 at 12:58 PM, Ajit Ratnaparkhi <ajit.ratnapar...@gmail.com> wrote: > Hi, > > This is about case where HDFS has some data blocks which are > over-replicated. > > Scenario is discussed below, > If one of datanodes goes down, Namenode will see some blocks as under > replicated and will start replication of under replicated blocks to bring > their replication level back to expected. If after that datanode which was > down comes up again without any data loss, at this time there will be blocks > having more replication level than expected. Does namenode itself take care > of removing extra blocks? or do we need to schedule balancer for that? > > -Ajit -- Harsh J
