“Big data” means data analysis of large data sets, systematic extraction of data from structured or unstructured data, breaking down data sets using traditional and latest data processing application, etc. Big data has three key concepts, which are volume, variety, and velocity. Furthermore, The concept of Big Data is immensely required in the sectors such as finance, retail, advertising, telecommunications, utilities, healthcare, pharmaceuticals, and Defense and intelligence. Henceforth, this field is equipped with various challenges that incorporate capturing data, search, sharing, data storage, data analysis, transfer, visualization, querying, data source, updating, and information privacy.
Big data deals with complex and large sets of data that cannot be handled using conventional software.
The three steps to deploying a Big Data solution are:
The three core methods of a reducer are,
Some of the real-time applications of Hadoop are in the fields of:
Yahoo, Facebook, Netflix, Amazon, and Twitter.
Standalone mode is Hadoop's default mode. It is primarily used for debugging purpose.
An EdgeNode is an interface that allows Hadoop to communicate with an outside network. Through it, client applications and Hadoop’s administration tools transfer data to the Hadoop cluster. EdgeNodes require enterprise-class storage facilities as they are highly efficient in managing multiple Hadoop clusters. Data management tools like Oozie, Pig and Flume work with EdgeNodes in Hadoop.
Another fairly simple question. Apache Hadoop is an open-source framework used for storing, processing, and analyzing complex unstructured data sets for deriving insights and actionable intelligence for businesses.
The three main components of Hadoop are-
This is one of the most introductory yet important Big Data interview questions. The answer to this is quite straightforward:
Big Data can be defined as a collection of complex unstructured or semi-structured data sets which have the potential to deliver actionable insights.
The four Vs of Big Data are –
Volume – Talks about the amount of data
Variety – Talks about the various formats of data
Velocity – Talks about the ever increasing speed at which the data is growing
Veracity – Talks about the degree of accuracy of data available
When we talk about Big Data, we talk about Hadoop. So, this is another Big Data interview question that you will definitely face in an interview.
Hadoop is an open-source framework for storing, processing, and analyzing complex unstructured data sets for deriving insights and intelligence.
Now that we’re in the zone of Hadoop, the next Big Data interview question you might face will revolve around the same.
The HDFS is Hadoop’s default storage unit and is responsible for storing different types of data in a distributed environment.
HDFS has the following two components:
NameNode – This is the master node that has the metadata information for all the data blocks in the HDFS.
DataNode – These are the nodes that act as slave nodes and are responsible for storing the data.
YARN, short for Yet Another Resource Negotiator, is responsible for managing resources and providing an execution environment for the said processes.
The two main components of YARN are –
ResourceManager – Responsible for allocating resources to respective NodeManagers based on the needs.
NodeManager – Executes tasks on every DataNode.
This is yet another Big Data interview question you’re most likely to come across in any interview you sit for.
Commodity Hardware refers to the minimal hardware resources needed to run the Apache Hadoop framework. Any hardware that supports Hadoop’s minimum requirements is known as ‘Commodity Hardware.’
FSCK stands for Filesystem Check. It is a command used to run a Hadoop summary report that describes the state of HDFS. It only checks for errors and does not correct them. This command can be executed on either the whole system or a subset of files.
The JPS command is used for testing the working of all the Hadoop daemons. It specifically tests daemons like NameNode, DataNode, ResourceManager, NodeManager and more.
(In any Big Data interview, you’re likely to find one question on JPS and its importance.)
This is one of the most important Big Data interview questions to help the interviewer gauge your knowledge of commands.
To start all the daemons:
./sbin/start-all.sh
To shut down all the daemons:
./sbin/stop-all.sh
This Hadoop interview questions test your awareness regarding the practical aspects of Big Data and Analytics.
In most cases, Hadoop helps in exploring and analyzing large and unstructured data sets. Hadoop offers storage, processing and data collection capabilities that help in analytics.
Listed in many Big Data Interview Questions and Answers, the best answer to this is –
Open-Source – Hadoop is an open-sourced platform. It allows the code to be rewritten or modified according to user and analytics requirements.
Scalability – Hadoop supports the addition of hardware resources to the new nodes.
Data Recovery – Hadoop follows replication which allows the recovery of data in the case of any failure.
Data Locality – This means that Hadoop moves the computation to the data and not the other way round. This way, the whole process speeds up.
NameNode – Port 50070
Task Tracker – Port 50060
Job Tracker – Port 50030
HDFS indexes data blocks based on their respective sizes. The end of a data block points to the address of where the next chunk of data blocks get stored. The DataNodes store the blocks of data while the NameNode manages these data blocks by using an in-memory image of all the files of said data blocks. Clients receive information related to data blocked from the NameNode.
Every business domain in current scenario is witnessing the job crisis. However, when it is about Big data, the job seekers in the respective technology are making a better move in their career. Artificial Intelligence (AI), Machine learning (ML), Internet of Things (IoT), Big Data, and other programming sectors are completely dependent on Big data analysis. Data Analyst and Data Scientist are the talent behind current technological expansion. Besides, Big data has occupied the topmost place in the arena of AI, ML, IoT, etc. A newly joined Big data candidate in an organization can expect a minimum salary of 38,000 dollars per annum. However, the salary of an experienced Big data expert always get the double of it. The salaries are very reliant upon the location, business, and the company’s requirements.
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