Start Quiz. 6. RDBMS works efficiently when there is an entity-relationship flow that is defined perfectly and therefore . . This set of MCQs helps students to learn about HDFS - Hadoop Distributed File System, which is the primary data storage system used by Hadoop applications. files having solved MCQs) are also welcomed. files having solved MCQs) are also welcomed. It saves the actual business data. With many organizations scrambling to utilize available data in the most efficient way possible . HDFS comprises of 3 important components-NameNode, DataNode and Secondary NameNode. Contributions through files (i.e. HDFS is more suitable for large amount of data sets in a single file as compared to small amount of data spread across multiple files. Q23. ~15 C. ~150 D. ~50 3. Difference Between Hadoop vs RDBMS. They would see Hadoop throw an concurrent File Access Exception when they try to access this file. YARN provides APIs for requesting and working with cluster resources, but . without requiring either the sender or receiver to be active during message transmission is suitable for . These Multiple Choice Questions (MCQ) should be practiced to improve the hadoop skills required for various interviews (campus interviews, walk-in interviews, company interviews), placements, entrance exams and other competitive examinations. It aggregates the results of the Map function andgenerates processed output. without requiring either the sender or receiver to be active during message transmission is suitable for . HDFS lacks the ability to support the random reading of small due to its high capacity design. HDFS File Read Workflow. Practice Hadoop HDFS MCQs Online Quiz Mock Test For Objective Interview. Fault tolerance. Topic wise solved MCQ's. Computer Science Engineering (CSE) . The Java language is used to develop HDFS. In addition, there are a number of DataNodes, usually one per node in the cluster, which manage storage attached to the nodes that they run on. Step 1: Client opens the file it wishes to read by calling open () on the FileSystem object, which for HDFS is an instance of DistributedFileSystem. There is one host onto which NameNode is running and the other hosts on which DataNodes are running. It saves the filesystem metadata, that is, files names, data about blocks of a file, blocks locations, permissions, etc. E.g. Distributed Computing MCQ. This architecture consist of a single NameNode performs the role of master, and multiple DataNodes performs the role of a slave. NameNode 2. Following are frequently asked questions in interviews for freshers as well experienced developer. NameNode The NameNode is the master daemon that operates on the master node. Datanodes store and maintain the blocks. Datanodes. 5. Both NameNode and DataNode are capable enough to run on commodity machines. HDFS operates on a Master-Slave architecture model where the NameNode acts as the master node for keeping a track of the storage cluster and the DataNode acts as a slave node summing up to the various systems within a Hadoop cluster. In talking about Hadoop clusters, first we need to define two terms: cluster and node. Hadoop is a framework written in Java for running applications on large clusters of commodity hardware and incorporates features similar to those of the Google File System (GFS) and of the MapReduce computing paradigm. The main difference between NameNode and DataNode in Hadoop is that the NameNode is the master node in Hadoop Distributed File . 97. It distributes the input to multiple nodes for processing. So, it is absolutely possible that two users try to write same file in HDFS. Velocity - Velocity is the rate at which data grows. Has less responsive time. NameNode grants a lease to the client who opens a file to write. A large number of many small files overload NameNode since it stores the namespace of HDFS. The NameNode is the centerpiece of an HDFS file system. Question 55 : In Singal's algorithm, the . Hadoop is an open source framework which is written in Java by apache software foundation. . Question 55 : In Singal's algorithm, the . C - Failure of one namenode causes loss of some metadata availability from the entire Datanodes send the block reports to the . We say process because a code would be running other programs beside Hadoop. . When same mapper runs on different dataset in different jobs. UGC NET practice Test Practice test for UGC NET Computer Science Paper. Image Credit: slidehshare.net. datanodes and namenode are two elementsof which file system? This set of MCQs helps students to learn about HDFS - Hadoop Distributed File System, which is the primary data storage system used by Hadoop applications. As such when a namenode is down, your cluster will be completely down, because Namenode is the single point of failure in a Hadoop Installation. The questions asked in this NET practice paper are from various previous year papers. C. It writes the output of the Map function to storage. Automatic garbage collection is the process of looking at heap memory, identifying which objects are in use and which are not, and deleting the unused objects. NameNode HDFS is implemented on any computer which can run Java can host a NameNode/DataNode on it. Explain the difference between NameNode, Checkpoint NameNode and BackupNode. Hadoop . UGC NET Previous year questions and practice sets GATE CSE Online Test Attempt a small test to analyze your preparation level. Point out the correct statement. Suppose there is another Hadoop cluster where the same data has been stored in larger chunks of size 200 MB each. Only the enabled policies are suitable for use with the command. Which of the following is the true about metadata? It keeps the directory tree of all files in the file system, and tracks where across the cluster the file data is kept. (a) Data Node (b) NameNode (c) Resource (d) Replication 9. The model which Apache Hadoop follows is known as a single writer multiple reader model. When Hadoop is not running in cluster mode . It would be an understatement in the current technology-driven employment landscape to say that data science and analytics are taking over the world. A. It works in-parallel on large clusters which could have 1000 of computers (Nodes) on the clusters. When the JobTracker is down, HDFS will still be functional but the MapReduce execution can not be started and the existing MapReduce jobs . 32MB 64MB 128MB 16MB For every node (Commodity hardware/System) in a cluster, there will be a _________. 13 . Computer Distributed Computing MCQ's : Pg-16; Question 451 : Which of the following is not a benefit of open distributed system (ODS) . The DataNode stores and retrieves the blocks when the NameNode asks. [-addPolicies -policyFile <file>] : Add a list of EC policies. Distributed Computing MCQ. HDFS has a master/slave architecture. What is full form of HDFS? Below listed are the main function performed by NameNode: Stores metadata of actual data. B. HDFS is suitable for storing data related to applications requiring low latency data access. Computer Distributed Computing MCQ's : Pg-16; Question 451 : Which of the following is not a benefit of open distributed system (ODS) . 2. b) NameNode is the SPOF in Hadoop 2.x c) NameNode keeps the image of the file system also d) Both (a) and (c) 18. 7. Contributions through files (i.e. 1) What is Hadoop Map Reduce? . . A. Hadoop File System B. Hadoop Field System C. Hadoop File Search D. It breaks the input into smaller components and distributes to other nodes in the cluster. Q 4 - What is the main problem faced while reading and writing data in parallel from . Means it is the data about the data being stored. HDFS strictly works on Write Once Read Many principle a. ( C) a) Gossip protocol b) Replicate protocol c) HDFS protocol d) Store and Forward protocol 19. An HDFS cluster consists of a single NameNode, a master server that manages the file system namespace and regulates access to files by clients. This GATE exam includes questions from previous year GATE papers. A. HDFS is not suitable for scenarios requiring multiple/simultaneous writes to the same file. The NameNode responds to the client request with the identity of the DataNode and the destination data block. To check whether Namenode is working or not, use the command /etc/init.d/hadoop- .20-namenode status or as simple as jps'. HDFS is designed to reliably store very large files across machines in a large cluster. DataNode The DataNodes are the slave daemon that operates on the slave nodes. DataNode DataNodes hold the actual data blocks and send block reports to the NameNode every 10 seconds. Volume - Amount of data in Petabytes and Exabytes. How Can We Check Whether Namenode Is Working Or Not? JobTracker monitors the individual TaskTrackers and the submits back the overall status of the job back to the client. A node is a process running on a virtual or physical machine or in a container. The partitioner determines which keys are processed on the same machine. . Then, NameNode checks whether the access to write has been granted to someone else earlier. Explain the difference between NameNode, Backup Node and Checkpoint NameNode. Ans: A botnet is a a type of bot running on an IRC network that has been created . are stored and maintained on the NameNode. Furthermore, you can discuss a MCQs on discussion page. C. Block D. ActionNode . ________ NameNode is used when the Primary NameNode goes down. They would see the current state of the file, up to the last bit written by the command. HDFS is suitable for storing large files with data having a streaming access pattern i.e. Jan 7, 2022. HBase stores the data in a column-oriented form and is known as the Hadoop database. Hive MCQ Quiz Interview Questions. If another client wants to write in that file, it seeks permission from NameNode for writing operation. S Hadoop A Datanode B Namenode C Block D None of the above Show Answer The default block size is ______. Active NameNode and Passive NameNode also known as stand by NameNode. Start Quiz There is only One NameNode process run on any hadoop cluster. As such when a namenode is down, your cluster will be completely down, because Namenode is the single point of failure in a Hadoop Installation. Which of the following scenario may not be a good fit for HDFS ? In which file system mapreduce function isused? We also accept requests for mcqs HERE. Answer and Explanation. A ________ serves as the master and there is only one NameNode per cluster. 2. It does not store the data of these files itself. NameNode uses . HDFS employs a NameNode and DataNode architecture to implement a distributed file system that provides high-performance access to data across highly scalable Hadoop clusters. The block size and replication factor are configurable per file. Please refer of 64 to 127. of Replicas, and also Slave related configuration. The NameNode is the centerpiece of an HDFS file system. It holds information about the various DataNodes, their location, the size of each block, etc. ~5s B. Get Big Data Multiple Choice Questions (MCQ Quiz) with answers and detailed solutions. 1. How many instances of NameNode run on a Hadoop Cluster? 2) How Hadoop MapReduce works? 32. What are the methods used for restarting the NameNode in Hadoop? How Can We Check Whether Namenode Is Working Or Not? . Question 53 : A middleware layer between the stub skeleton and transport. The size of the metadata for storing information for a single chunk in the system is 10 KB. They would see the content of the file through the last completed block. B. As you know, HDFS stands for Hadoop Distributed File System. NameNode ports: 50470 → 9871, 50070 → 9870, and 8020 → 9820 Secondary NameNode ports: 50091 . The blocks of a file are replicated for fault tolerance. This is because Namenode is a very expensive high performance system, so it is not prudent to occupy the space in the Namenode by unnecessary amount of metadata that is generated for . Big Data Quiz. This Apache Hadoop Quiz will help you to revise your Hadoop concepts and check your Big Data knowledge. Hadoop creates one map task for each split, which runs the userdefined map function for each record in the split. Data analysis uses a two-step map and reduce process. Automated MCQs based on Hadoop provided by Helpdice to enhance and test deep knowledge of the topic. 1) Replicating data oon multiple data nodes helps achieve which of the characteristic of Hadoop (HDFS) High Availability. Adding policy will fail if there are already 64 policies added. Clarification: All the metadata related to HDFS including the information about data nodes, files stored on HDFS, and Replication, etc. Hadoop daemons run on a cluster of machines. The data lakes can be built on HDFS (i.e. The namenode is the commodity hardware that contains the GNU/Linux operating system and the namenode software. Filename, Path, No. Q.What do you mean by word Data Science? Hadoop's HDFS is a highly fault-tolerant distributed file system and, like Hadoop in general, designed to be deployed on low-cost hardware. ( C) a) Gossip protocol b) Replicate protocol c) HDFS protocol d) Store and Forward protocol 19. So any machine that supports Java language can easily run the NameNode and DataNode software. HDFS employs a NameNode and DataNode architecture to implement a distributed file system that provides high-performance access to data across highly scalable Hadoop clusters. Answer (1 of 7): Here, Client is nothing but the machine you have logged in to work on Hadoop cluster. Social media contributes a major role in the velocity of growing data. This framework is used to write software application which requires to process a vast amount of data (It could handle multi-terabytes of data). As input, you are given one le that contains a single line of text: Hadoop Distributed File System (HDFS): The Hadoop Distributed File System (HDFS) is the primary storage system used by Hadoop applications. Answer: The five V's of Big data is as follows: Volume - Volume represents the volume i.e. While there is only one namenode, there can be multiple datanodes, which are responsible for retrieving the blocks when requested by the namenode. Veracity - Degree of the accuracy of data available. It stores each file as a sequence of blocks; all blocks in a file except the last block are the same size. NameNode tries to keep the first copy of data nearest to the client machine. Explain what happens in textinformat ? Q23. For processing large data sets in parallel across a Hadoop cluster, Hadoop MapReduce framework is used. A cluster is a collection of nodes. The High available Hadoop cluster also has 2 or more than two Name Node i.e. NameNode NameNode is the master service that hosts metadata in disk and RAM. write the data once to files and read as many times required. An unused or . Ans: Data Science is the extraction of knowledge from large volumes of data that are structured or unstructured, which is a continuation of the field data mining and predictive analytics, It is also known as knowledge discovery and data mining Q.Explain the term botnet? 1. In case if Active NameNode fails then the Passive node will take the responsibility of Active Node and provide the same data as that of Active NameNode which can easily be utilized by the user. Value is the content of the line Question 52 : Which of the following algorithms is less sensitive to crashes. The methods used for restarting the NameNodes are the following: You can use /sbin/hadoop-daemon.sh stop namenode command for stopping the NameNode individually and then start the NameNode using /sbin/hadoop-daemon.sh start namenode. The namenode checks the privileges of the client and gives permission to read or write on the data blocks. Suppose there is a Hadoop Cluster that contains 1,000 files of size 2 MB each, with the chunk size equal to the file size. It does not store the data of these files itself. Therefore, NodeManager installs on every DataNode. Answers to all these Hadoop Quiz Questions are also provided along with them, it will help you to brush up your . JobTracker process is critical to the Hadoop cluster in terms of MapReduce execution. It manages the Datanodes. When same mapper runs on the different dataset in same job. NameNode tries to keep the first copy of data nearest to the client machine. Big Data Quiz : This Big Data Expert Hadoop Quiz contains set of 60 Big Data Quiz which will help to clear any exam which is designed for Expert. Answer: B. There is only One NameNode process run on any hadoop cluster. It is not suitable for a large number of small files. To check whether Namenode is working or not, use the command /etc/init.d/hadoop- .20-namenode status or as simple as jps'. NameNode: NameNode can be considered as . S Hadoop A 32MB B 64MB C 128MB D 16MB _____ NameNode is used when the Primary NameNode goes down. Regulates client's access to files. Top 40 Hadoop Interview Questions in 2022. It will increase your confidence while appearing for Hadoop interviews to land your dream Big Data jobs in India and abroad. You need to move a file titled "weblogs" into HDFS. This Site provides MCQ Questions & Answers for IT Companies Interview, technical interview, competitive exam, GATE Entrance, Placement interview, etc. Multiple Choice Questions on "Introduction to HDFS". b) NameNode is the SPOF in Hadoop 2.x c) NameNode keeps the image of the file system also d) Both (a) and (c) 18. NameNode - It works as Master in Hadoop cluster. Small files are smaller than the HDFS Block size (default 128MB). During start up, the ___________ loads the file system state from the fsimage and the edits log file. Namenode Block None of the above The default block size is ______. S Hadoop A Rack B Data C Secondary D Both A and B Show Answer The minimum amount of data that HDFS can read or write is called a _____________. B - Each namenode manages metadata of a portion of the filesystem. Explanation: Hadoop divides the input to a MapReduce job into fixed-size pieces called input splits, or just splits. Q22. 1) What is identity mapper in hadoop. How many instances of NameNode run on a Hadoop Cluster? Apache YARN (Yet Another Resource Negotiator) is Hadoop's cluster resource management system. Hadoop software framework work is very well structured semi-structured and unstructured data. Velocity - Everyday data growth which includes conversations in forums, blogs, social media posts, etc. a) DataNode is the slave/worker node and holds the user data in the form of Data Blocks b) Each incoming file is broken into 32 MB by default c) Data blocks are replicated across different nodes in the cluster to ensure a low degree of fault tolerance d) None of the mentioned a) As HDFS was designed to work with a small number of large files for storing large . HDFS provides high throughput access to application data HDFS is not designed to support very large files HDFS is suitable for applications that have large data sets. . the data of the files is not stored on the NameNode but rather it has the directory tree of all the files present in the HDFS file system on a hadoop cluster. We also accept requests for mcqs HERE. Download these Free Big Data MCQ Quiz Pdf and prepare for your upcoming exams Like Banking, SSC, Railway, UPSC, State PSC. Massively Parallel Processing) databases like Amazon Redshift, Azure SQL Data warehouse, GCP's BigQuery, etc are built for online analytics of large volume of highly structured data.. Topic wise solved MCQ's. Computer Science Engineering (CSE) . The input is read line by line. 12325. Gets only the block locations form the namenode B. Q22. Question 53 : A middleware layer between the stub skeleton and transport. Question 54 : In ----- Any read on a data item x returns a value corresponding to the results of the most recent write on x. Question 52 : Which of the following algorithms is less sensitive to crashes. NameNode, a master server that manages the file system namespace and regulates access to files by clients. Namenode splits big files into smaller blocks and sends them to different datanodes Namenode is responsible for assigning names to each slave node so that they can be . B. Streaming access to file system data. Hadoop clusters 101. An in-use object, or a referenced object, means that some part of your program still maintains a pointer to that object. This option is correct. (a) DataNode (b) NameNode (c) ActionNode (d) None of the mentioned 10.In HDFS the files cannot be (a) read (b) deleted (c) executed (d) Archived In textinputformat, each line in the text file is a record. This also supports a variety of data formats in real-time such as XML, JSON, and text-based flat file formats. which is responsible for asking the namenode to allocate new blocks by picking a list of suitable datanodes to store the replicas . The mechanism used to create replica in HDFS is____________. Step 2: DistributedFileSystem calls the NameNode using RPC to determine the locations of the blocks for the first few blocks in the file. Furthermore, you can discuss a MCQs on discussion page. We can say that NameNode is the centerpiece of an HDFS file system which is responsible for keeping the record of all the files in the file system, and tracks the file data across the cluster or multiple machines. Then the client flushes the block of data from the local temporary file to the specified DataNode. Consider Hadoop's WordCount program: for a given text, compute the frequency of each word in it. _____ NameNode is used when the Primary NameNode goes down. It is a software that can be run on commodity hardware. Answer: NameNode is the core of HDFS which will manage the metadata - the information about the file can be mapped to block locations and the blocks are stored on which datanode. The NameNode and DataNode are pieces of software designed to run on commodity machines. Variety - Includes formats like videos, audio sources, textual data, etc. YARN was introduced in Hadoop 2 to improve the MapReduce implementation, but it is general enough to support other distributed computing paradigms as well. It keeps the directory tree of all files in the file system, and tracks where across the cluster the file data is kept. In addition, there are a number of DataNodes, usually one per node in the cluster, which manage storage attached to the nodes that they run on. Rack; Data; Secondary; primary . Rack; Data; Secondary; primary . Big data MCQ question Section covers from all chapter. of blocks, Block IDs, Block Location, No. data volume in Petabytes. C - IS suitable for read and write many times D - Works better on unstructured and semi-structured data. Open-Source - Hadoop is an open-sourced platform. If you are storing these huge numbers of small files, HDFS cannot handle these lots of small files. . NameNode: NameNode is at the heart of the HDFS file system which manages the metadata i.e. Share. Hadoop is suitable for massively offline batch processing of structured, semi-structured & unstructured data by building a data lake whereas MPP (i.e. datanodes and namenode are two elementsof which file system? Listed in many Big Data Interview Questions and Answers, the best answer to this is -. Java garbage collection is an automatic process. The system having the namenode acts as the master server and it does the following tasks − Manages the file system namespace. A. amount of data that is growing at a high rate i.e. NameNode is a node, where Hadoop stores all the file location information in HDFS (Hadoop Distributed File System). 25.What is a Namenode? Hadoop DPE Quiz. What should be an upper limit for counters of a Map Reduce job? -. It also manages Filesystem namespace. However, Hive is most suitable for data warehouse applications because it: Analyzes relatively static data. Question 54 : In ----- Any read on a data item x returns a value corresponding to the results of the most recent write on x. Gets the data from the namenode C. Gets both the data and block location from the namenode D. Gets the block location from the datanode 2. In Hadoop, HBase is the NoSQL database that runs on top of HDFS. Scalability - Hadoop supports the addition of hardware resources to the new nodes. The mechanism used to create replica in HDFS is____________. A. Great Learning Team. Advantage is it decreases the number of files stored in namenode and the archived file can be queried using hive. Datanode Namenode Block None of the above Which of the following is not Features Of HDFS? The disadvantage is it will cause less efficient query . By. Chapter 4. 50. YARN. NameNode and DataNodes. In which file system mapreduce function isused? The five Vs of Big Data are -. It allows the code to be rewritten or modified according to user and analytics requirements. Hadoop DPE Quiz contain set of 30 MCQ questions for Hadoop DPE MCQ which will help you to clear beginner level quiz. . It is suitable for the distributed storage and processing. It is suitable for the distributed storage and processing. Jobtracker and namenode detect the failure On the failed node all tasks are re‐scheduled Namenode replicates the users data to another node 14.
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