juniorHadoop
What is block size in HDFS?
Updated May 16, 2026
Short answer
Block size is the unit in which HDFS stores data.
Deep explanation
Large block sizes reduce metadata overhead and improve throughput.
Real-world example
128MB or 256MB blocks for big data files.
Common mistakes
- Using small block sizes for large datasets.
Follow-up questions
- Default block size?
- Why large blocks?