Top 6 Microsoft HDFS Interview Questions

Hari Bhutanadhu 10 Mar, 2023
8 min read


Microsoft Azure HDInsight(or Microsoft HDFS) is a cloud-based Hadoop Distributed File System version. A distributed file system runs on commodity hardware and manages massive data collections. It is a fully managed cloud-based environment for analyzing and processing enormous volumes of data. HDInsight works seamlessly with the Hadoop ecosystem, which includes technologies like MapReduce, Hive, Pig, and Spark. It is also compatible with Microsoft’s powerful data processing technologies like Azure Data Lake Storage and Azure Blob Storage.

Scalability is one of HDInsight’s most essential characteristics. Microsoft Azure HDInsight also has enterprise-level security features, including role-based access control, encryption, and network isolation. HDInsight integrates readily with Microsoft’s other cloud services, including Power BI, Azure Stream Analytics, and Azure Data Factory. Finally, it is a fully managed cloud-based service, which means Microsoft is responsible for the underlying infrastructure, maintenance, and upgrades.

Microsoft HDFS Architecture

Learning Objectives

  1. We will review Microsoft HDFS and how it works in a significant data context.
  2. Understanding how to utilize Azure HDInsight in the cloud to handle and analyze enormous volumes of data
  3. We will review Hadoop tools such as MapReduce, Hive, and Spark and how they may be utilized with HDInsight.
  4. You will also learn about the functions of different nodes in HDInsight.

This article was published as a part of the Data Science Blogathon.

Table of Contents

Azure’s HDInsight is a fully managed cloud solution running significant data processing technologies like Apache Hadoop and Apache Spark. It’s a cloud-based Hadoop implementation for massive data processing and analysis in a distributed system. Hadoop is a freely available software framework for sharing enormous datasets among computing nodes. It plays a crucial role in the overall Hadoop infrastructure. It is a distributed file system that stores application data on inexpensive commodity servers in several locations, making it accessible at high speeds. HDFS’s master/slave architecture ensures that even the most massive datasets may be stored and managed without any loss of integrity or performance.

HDInsight’s distributed file system is HDFS. When users submit tasks to HDInsight, the data is dispersed automatically among the cluster nodes and saved in HDFS. HDInsight also includes other Hadoop ecosystem components such as MapReduce, Hive, Pig, and Spark for processing and analyzing data in HDFS. HDInsight is a cloud-based platform that enables customers to leverage the capabilities of Hadoop and its ecosystem products without requiring underlying infrastructure management. It uses HDFS as its file system to facilitate distributed data storage and processing.

HDInsight and HDFS Relationship


Q2. How Does Microsoft Azure Data Lake Storage Gen2 Work with HDFS?

Microsoft Azure Data Lake Storage Gen2 is a cloud-based storage solution with a hierarchical file system for storing and analyzing massive volumes of data. It is intended to interact with large data processing platforms like Hadoop and Spark and smoothly interfaces with HDFS. Azure Data Lake Storage Gen2 includes a Hadoop Compatible File System (HCFS) interface, allowing Hadoop and other big data processing tools to access data in Data Lake Storage Gen2 as if it were in HDFS. Customers may handle and analyze data stored in Data Lake Storage Gen2 using their existing Hadoop tools and applications.

When Hadoop jobs are executed on HDInsight, the data is automatically distributed across the nodes in the cluster and stored in HDFS. However, Azure Data Lake Storage Gen2 can store data directly in the storage account without creating an HDInsight collection. This data can then be accessed using the HCFS interface, which provides the same functionality as HDFS. Azure Data Lake Storage Gen2 also offers advanced features such as Azure Blob Storage integration, Azure Active Directory integration, and enterprise-grade security features such as role-based access control and encryption. Overall, Data Lake Storage Gen2 provides a scalable and secure storage solution for big data processing and analysis, and it seamlessly integrates with Hadoop and HDFS.

Microsoft Azure Data Lake Storage Gen2 work with HDFS

Q3. Can You Explain the Role of NameNode and DataNode in HDFS?

The NameNode and DataNode components of HDFS create a distributed storage and processing environment for massive datasets. Here is how they work:

  1. NameNode: The NameNode serves as the HDFS cluster’s central coordinator and metadata store. It maintains information about file locations, hierarchy, and file and directory properties. The NameNode stores this information in memory and on disc, and it is in charge of managing access to HDFS data. When a client application needs to read or write data from HDFS, it first contacts the NameNode to retrieve the data’s location and other information.
  2. DataNode: The DataNode is HDFS’s workhorse. It is responsible for storing the data blocks that make up the files in HDFS. Each DataNode manages storage for a subset of the data in the HDFS cluster and duplicates data to other DataNodes for redundancy and fault tolerance. When a client application needs to read or write data, it directly talks with the data nodes that hold the data blocks.

In summary, the NameNode and DataNode collaborate to produce a distributed file system capable of storing and processing massive datasets. The NameNode handles the file information, whereas the DataNodes contain the actual data blocks. To provide data redundancy, fault tolerance, and rapid data retrieval, the NameNode and DataNodes interact with one another.

Q4. How does HDFS ensure data reliability and fault tolerance?

It is intended to offer fault-tolerant storage for massive datasets. It does this by duplicating data over several cluster nodes, detecting and recovering from faults, and maintaining data storage reliability and accuracy. HDFS ensures data reliability and fault tolerance in the following ways:

  1. It stores data in blocks duplicated across several data nodes in the cluster. Each block is replicated three times by default, although this may be changed based on the application’s needs. Data replication over several nodes guarantees that data is available on other nodes even if one or more fails.
  2. Failure detection and recovery: HDFS continually checks the health of the cluster’s data nodes. Whenever a DataNode fails or becomes unresponsive, the NameNode notices the failure and duplicates the failed node’s data to other nodes in the cluster. The NameNode then updates the metadata to reflect the new locations of the replicated data blocks.
  3. Data consistency: Using a write-once-read-many (WORM) architecture, HDFS ensures that data is saved reliably and precisely. Data that has been written to HDFS cannot be changed. This guarantees that data consistency is maintained even when numerous clients access the same data simultaneously.
  4. Block placement: To guarantee that data blocks are placed on distinct racks in the cluster, HDFS employs a rack-aware placement strategy. This ensures that even if an entire frame fails, the data is still accessible on the cluster’s other racks.

Overall, by duplicating data over several nodes, detecting and recovering from failures, assuring data consistency, and employing a rack-aware placement policy to reduce data loss due to rack failures, HDFS provides a dependable and fault-tolerant storage solution for massive datasets.

HDFS ensure data reliability and fault tolerance

Q5. Can You Describe What the NameNode and DataNode Roles are in HDFS?

HDFS is a distributed file system that stores and handles massive datasets on commodity hardware in a cluster. As explained in the preceding question, the HDFS architecture comprises two key components: the NameNode and the DataNode.To provide data dependability and fault tolerance, the NameNode and DataNodes interact. When a client needs to read or write data from HDFS, it talks with the NameNode to find the data blocks. The client then discusses with the DataNodes directly to read or write data blocks.

MapReduce, a distributed data processing framework, is frequently combined with HDFS. MapReduce is intended to handle big datasets by dividing them into smaller pieces, spreading the processing of those chunks across a cluster of processors, and aggregating the results. Here is how MapReduce interacts with HDFS:

  1. The input data is saved in HDFS. MapReduce receives input data from HDFS and divides it into smaller chunks called input splits.
  2. The input splits are distributed across the cluster and assigned to specific Map jobs using MapReduce. Each Map job handles a single input split and produces intermediate key-value pairs.
  3. The intermediate key-value pairs are then sorted and shuffled before being sent to the Reduce jobs. Each Reduce job collects intermediate input and generates the final result.
  4. The final result is saved to HDFS.

Overall, HDFS and MapReduce collaborate to create a scalable, fault-tolerant architecture for massive dataset processing. It offers dependable storage for input and output data, whereas MapReduce spreads data processing throughout the cluster.


Q6.What makes HDFS different from other file systems, and what are the benefits of using HDFS in a huge data environment?

HDFS varies from standard file systems in numerous crucial areas, and these distinctions bring several benefits when working with huge amounts of data. These are some important distinctions and advantages of utilizing HDFS in a large data environment:

  1. Scalability: Conventional file systems are not built to manage the massive amounts of data that are frequent in big data situations. It is designed to grow horizontally, which means it can accommodate petabytes or even exabytes of data storage and processing by distributing the data over a cluster of commodity hardware.
  2. Fault tolerance: It is built to be fault-tolerant. It can endure the failure of individual nodes in the cluster by duplicating data across several nodes in the cluster. It also has techniques for automatically detecting and recovering from node failures.
  3. It is meant to have a high throughput for both reading and writing data. While working with huge files, HDFS may achieve fast read and write rates since it is specialized for massive data transfers.
  4. Data locality: It is designed to maximize data locality, which means that data is stored and processed on the same cluster nodes wherever feasible. Reducing data transit over the network minimizes network traffic and increases performance.
  5. Cost-effectiveness: Because it is designed to run on commodity hardware, it may be implemented on low-cost servers or in the cloud. As a result, it provides a low-cost option for storing and processing massive volumes of data.

Overall, the benefits of employing HDFS in a big data context are scalability, fault tolerance, high throughput, data localization, and cost-effectiveness. By exploiting these features, organizations may store, manage, and analyze massive datasets more efficiently and cost-effectively than traditional file systems.



In this article, we examined different features of Microsoft HDFS, including its introduction, architecture, working with Azure Data Lake Storage Gen2, and its function in MapReduce. We also went through common interview questions in both Amazon and Microsoft setups. It is important to big data applications because it provides scalable and fault-tolerant storage for massive datasets. Understanding design and operation is essential for data engineers and developers working with big data solutions.

Here are some key takeaway points:

  1. It is a distributed file system that stores and handles huge datasets on commodity hardware in a cluster.
  2. The NameNode and the DataNode are the two fundamental components of HDFS. The NameNode keeps the file system’s information, whereas the DataNode stores the actual data blocks that comprise the files.
  3. It is built to be extremely fault-tolerant and to provide dependable storage for big data applications. It can accommodate petabytes or even exabytes of data storage and processing by spreading the data across a cluster of commodity computers.
  4. MapReduce, a distributed data processing framework, may be used in combination with HDFS. MapReduce divides huge datasets into smaller bits and distributes their processing over a cluster of processors.
  5. Lastly, Microsoft provides HDInsight, a cloud-based Hadoop distribution containing HDFS, MapReduce, and other components.

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Hari Bhutanadhu 10 Mar, 2023

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