PYQ-backed sure-shot questions, unit-wise strategies, diagrams, and exam writing tips — built specifically for AKTU 2025-26.
Unit I introduces what Big Data is and why it matters. Big Data = data so large/fast/varied that traditional tools can't handle it. Think of data from Facebook, YouTube, IoT sensors — all generated every second. The key exam topics are the 5 Vs (Volume, Velocity, Variety, Veracity, Value) and distinguishing analysis from reporting.
Hadoop is an open-source framework to store and process Big Data in a distributed cluster. MapReduce is Hadoop's processing engine — it breaks big tasks into smaller parallel tasks. Think of it like a restaurant: Map = each chef prepares their dish separately; Reduce = waiter combines and serves everything.
HDFS = Hadoop Distributed File System. Stores huge files split into 128MB blocks across many machines. NameNode = brain (stores metadata, doesn't store data). DataNode = worker (stores actual data blocks). Each block replicated 3 times for fault tolerance. Think of it like a library: NameNode is the index catalogue, DataNodes are the book shelves.
YARN = Yet Another Resource Negotiator — Hadoop's resource manager. It separates resource management from processing. NoSQL = "Not Only SQL" — flexible databases for unstructured data (MongoDB, Cassandra, Redis). Spark = faster alternative to MapReduce because it processes data in memory (RAM) instead of disk. RDD = Resilient Distributed Dataset — Spark's core data structure.
Apache Pig = high-level data flow language (Pig Latin). Procedural — you tell it HOW to process. Good for ETL (Extract-Transform-Load). Apache Hive = data warehouse, uses HiveQL (SQL-like). Declarative — you tell it WHAT you want. Good for analysis/reporting. HBase = NoSQL database built on HDFS, column-family store, real-time read/write.
Underline these words when they appear in your answers. Examiners scan for them.
If you have only one night — study these and nothing else. These 8 topics alone can get you 50+ marks.