Wednesday 5 April 2017

Block

Block

  • Internally, a file is split it into one or more block.
  • In Hadoop 1.0 the default block size is 64MB.
  • In Hadoop 2.0 the default block size is 128MB
  • We can customize this size in configuration level.
  • These split-ted blocks will be stored in data nodes.
  • Each block will be stored in different Data nodes to get fault tolerant.
  • Hadoop maintains replication factor,by default replication factor is 3. 
  • We can customize this value 
    • At the cluster level 
    • At file creation 
    • Later stage for stored file
Thanks for your time. 
Nireekshan