What is slot in Hadoop v1 Map-Reduce ?

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    • #4698
      DataFlair TeamDataFlair Team

      What are the slots?
      how many types or slots are there?
      What are the issues with the slot based mechanism ?

      why it was removed from Hadoop 2 ?

    • #4699
      DataFlair TeamDataFlair Team

      Each Map Reduce Jobs are split into task and Task tracker runs each task on a fixed number of map and reduce slots inside a data node based on a static configuration.

      In Hadoop 1.0 we need to specify in mapred-site.xml the following parameter to Configure the number of map slots and reduce slots


      The Following are the problem with Slot

      • Slots are wasted, anytime the cluster workload does not fit the static configuration.
      • In a slot-based model makes it hard for non-MapReduce applications to be scheduled appropriately.
      • Jobs never leave their original slots and cannot be move to free slots.

      For more details about MapReduce Jobs, please refer: MapReduce Tutorial

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