Web-ui shows that half of the datanodes are in decommissioning mode. What does that mean? Is it safe to remove those nodes from the network?

443

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What is the difference between a hadoop database and relational database?

453

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Can we deploye job tracker other than name node?

656

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What is difference between secondary namenode, checkpoint namenode & backupnode?

467

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Name the most common input formats defined in hadoop?

443

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Which one is default?

480

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Is it possible to have hadoop job output in multiple directories?

431

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What is tasktracker in hadoop?

428

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What is a combiner in hadoop?

510

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Have you ever used counters in hadoop?

421

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What are some typical functions of job tracker in hadoop?

416

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Can you define inputsplit in hadoop?

464

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What daemons run on master nodes?

481

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Can you explain rack awareness?

430

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Can you explain record reader?

431

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