Top 20 Interview questions for Big Data
- WHAT IS BIG DATA?
Big Data is a term that describes a large amount of data. That can come in a structured form and unstructured form. But it is not that amount of data that is required. Data Scientist’s Job is to extract output from that large amount of data by calculations and technology.
- WHAT IS FIVE V(S) FOR BIG DATA?
Volume, variety, velocity, veracity, value – are the five v(s) for Big Data. When your interviewer will ask you what is Big Data you can add all these to add flavor to your answer.
- HOW BIG DATA AND HADOOP INTERRELATED TO EACH OTHER?
Big Data Hadoop is a famous term in the field of Big Data. Hadoop is a framework that specializes in big data operations. It is used by big data analysts to help businesses to make decisions Big Data Technologies.
- WHAT ARE THE STEPS TO BE FOLLOWED TO DEPLOY BIG DATA?
- Data ingestion: Extraction of data from various resources is called data ingestion. It can be ingested from batch jobs or real-time streaming.
- Data storage: It is the process of storing big data through Big Data Tools.
- Data processing: It is the final step of data processing through Data Analysis Tools. Data, extracted from Big Data either is stored in HDFS or NoSQL database.
- WHY BIG DATA ANALYTICS USE HADOOP?
Nowadays data analysis has become one of the new parameters of businesses and almost 140000 to 190000 data analytics are working worldwide. Hadoop is an open source distributive framework which helps in Big Data storage, processing, and data collection.
- WHAT IS THE COMMAND TO FORMAT BIG DATA?
$ HDFS name code format
- DO YOU OPTIMIZE ALGORITHM OR CODE TO MAKE IT GROW FASTER?
The answer should be yes because real-world performance matters and the interviewer may ask you about your previous projects. It is a common question for Big Data Scientists or Big Data Analytics.
- WHICH HARDWARE CONFIGURATION IS NEEDED FOR BIG DATA?
Dual processors or core machines with a configuration of 4 / 8 GB RAM and ECC memory is needed for Big Data Hadoop operations.
- CAN TWO USERS AT THE SAME TIME TAKE ACCESS IN THE SAME FILE OF HDFS DATABASE?
HDFS NameNode supports exclusive write. Hence, only the first user can receive the grant to access files and the second user will be rejected.
- WHAT ARE THE COMMON INPUT FORMATS IN HADOOP?
- Text input format
- Sequence file input format
- Key value input format
- WHAT ARE THE IMPORTANT FEATURES OF BIG DATA HADOOP?
- Open source
- Fault tolerance
- Distributed processing
- High availability
- WHAT ARE THE BIG DATA ANALYSIS TOOLS?
- AZURE HD INSIGHT: It is a spark and Hadoop service in the cloud.
- SKYTREE: It is a Big Data Analytics Tools to empower data scientists to build more accurate models.
- TALEND: It is a Big Data Toolwhich simplifies and automates Big Data integration
- WHAT ARE THE BENEFITS OF BIG DATA?
Through the extract of Big Data, we can save cost, reduce the time of some laborious works, understand the market conditions, control online reputation, etc.
- WHAT ARE THE THREE RUNNING MODES OF BIG DATA HADOOP?
- STANDALONE OR LOCAL
- FULLY DISTRIBUTED
- HOW DOES HADOOP MAPREDUCE WORK?
- MAP PHASE: Here input data is split by map tasks. It runs in parallel. This is used for analysis purpose
- REDUCE PHASE: In this phase split data is aggregated from the entire collection and the result is shown.
- WHAT ARE THE PORT NUMBERS FOR NAMENODE, JOB TRACKER AND TASK TRACKER?
- NameNode– Port 50070
- Job Tracker– Port 50030
- Task Tracker– Port 50060
- WHAT CAN BE BASIC PARAMETRES OF MAPPER in BIG DATA?
- LongWritable and Text
- Text andIntWritable
- WHAT WILL HAPPEN IF A NAMENODE DO NOT HAVE DATA?
This is a trick question by an interviewer if there is no data in the name node that will not exist in Big Data Hadoop.
- WHAT IS SEQUENCE FILE INPUT FORMAT IN BIG DATA?
It is an input format to read a sequence file. It stores data in sterilized key-value pair.
- WHAT ARE ACTIVE AND PASSIVE NAMENODES IN BIG DATA APPLICATIONS?
- Active NameNode is the NameNode which works and runs in the cluster of Big Data.
- Passive NameNode is a standby NameNode that has similar data as activeNameNodein Big Data.