HDFS is the Hadoop Distributed File System, is the storage layer for Hadoop. The files in HDFS are split into block-size parts called data blocks. These blocks are saved on the slave nodes in the cluster. By default, the size of the block is 128 MB by default, which can be configured as per our necessities. It follows the master-slave architecture. It contains two daemons- DataNodes and NameNode.
A) NameNode
The NameNode is the master daemon that operates on the master node. It saves the filesystem metadata, that is, files names, data about blocks of a file, blocks locations, permissions, etc. It manages the Datanodes.
B) DataNode
The DataNodes are the slave daemon that operates on the slave nodes. It saves the actual business data. It serves the client read/write requests based on the NameNode instructions. It stores the blocks of the files, and NameNode stores the metadata like block locations, permission, etc.
Posted Date:- 2021-08-31 04:59:30
Write the command used to copy data from the local system onto HDFS?
Explain the usage of Context Object.
Whenever a client submits a hadoop job, who receives it?
What is a rack awareness and on what basis is data stored in a rack?
How can you skip the bad records in Hadoop?
What is the process to change the files at arbitrary locations in HDFS?
Where does Hive store the table data by default?
Explain about the process of inter cluster data copying.
What is the default replication factor?
Mention features of Apache sqoop.
What do you mean by SerDe in Hive? Explain.
Mention a business use case where you worked with the Hadoop Ecosystem
What is meant by over/under- replicated blocks in Hadoop?
Explain the difference between HBase and Hive.
Explain the three core methods of a reducer.
What are the Benefits of using zookeeper?
How can you restart the NameNode in Hadoop?
What makes Hadoop Fault tolerant?
How will you choose various file formats for storing and processing data using Apache Hadoop ?
What are the steps involved in deploying a big data solution?
What are the most commonly defined input formats in Hadoop?
What is the best hardware configuration to run Hadoop?
What are the main components of a Hadoop Application?
On what concept the Hadoop framework works?
What is the port number for NameNode?
Explain how data is stored in a rack.
Compare HDFS with Network Attached Storage (NAS).
What is meant by a block and block scanner?
What is indexing? How is indexing done in HDFS?
Explain the difference between HDFS and regular FileSystem.
What is shuffling in MapReduce?
What are the Limitations of Hadoop 1.0 ?
Name some companies that use Hadoop.
What are some limitations of Hadoop?
What are the three modes in which Hadoop runs?
How big data analysis helps businesses increase their revenue? Give example.
What do the four V’s of Big Data denote?
Explain the Storage Unit In Hadoop (HDFS).
What are the challenges faced with Big Data, and why do we use Hadoop for Big Data?