How does Namenode decides in which datanode to write a block

How does Namenode decides in which datanode to write a block



1.HDFS Architecture Guide - Apache Hadoop

Description:HDFS applications need a write-once-read ... The DataNode does
not create all ... and allocates a data block for it. The NameNode
responds to the client request ...



2.Hadoop - HDFS

Description:Also each datanode passes on the block to next datanode to
write, ... Interestingly client and NN does not wait till ... It also
sends the block report to namenode ...



3.NameNode - Hadoop Wiki - FrontPage - General Wiki

Description:The NameNode responds the successful requests by returning a
list of relevant DataNode servers ... or the smaller the block size. Use
... If a NameNode does not ...



4.The Architecture of Open Source Applications: The Hadoop ...

Description:The NameNode records changes to HDFS in a write-ahead log ...
If the NameNode does not receive a ... Each DataNode runs a block scanner
that ...



5.FAQ - Hadoop Wiki - FrontPage - General Wiki

Description:Does HDFS make block boundaries between records? ... On an
individual data node, ... The NameNode does not have any available
DataNodes.



6.HDFS Architecture - Decomposition

Description:If a substantial amount of time passed since the last DataNode
block report then NameNode ... or to write new block ... a NameNode does
not connect to a DataNode ...



7.Hadoop Distributed File System-2.2.0 - Federation

Description:Block Storage Service has two ... (which is done in Namenode)
Provides datanode cluster membership ... The failure of a Namenode does
not prevent the datanode from ...



8.Hadoop Distributed File System (HDFS) Overview

Description:Namenode Management Node SAME BLOCK hamlet.txt file = ... •
Namenode does NOT directly write or read data – One of the reasons for
HDFS's Scalability



9.Hadoop - HDFS: HDFS - Write Anatomy

Description:04-01-2012 · ... write directly to datanode. However each
datanodes has to notify receipt of each block back to client and namenode.
... does the client try to rewrite ...



10.NameNode (Hadoop 0.13.1 API)

Description:A client that wants to write an additional block to ... The
name node does not enter ... allows the DataNode to tell the NameNode
about recently-received block data ...