System-design

Understand the internal architecture of a distributed file system (DFS), including key components like metadata servers, data nodes, replication mechanisms, and a real-world example using Hadoop HDFS.

Learn what a Distributed File System is, how it works, its key features, examples like HDFS and GFS, and common use cases such as cloud storage and big data processing.

A Composite Index combines two or more columns into a single index to speed up queries filtering or sorting by multiple fields. Column order matters, and the index supports queries starting with the leftmost column(s).

A Unique Index enforces distinct values in a column, preventing duplicates while speeding up queries. It's ideal for fields like email or username, ensuring data accuracy with minimal impact on read performance.

A checksum is a fixed-length string from a cryptographic hash that verifies data integrity in distributed systems. It helps detect corruption during data transfer, ensuring clients receive error-free data or can request a clean copy.