> For the complete documentation index, see [llms.txt](https://bigdata-2.gitbook.io/bd201notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bigdata-2.gitbook.io/bd201notes/topics-for-writiing-task/hdfs.md).

# HDFS

* HDFS node types. What is the purpose of each of them?
* How HDFS achieves Fault Tolerance?
* Block size. Physical space allocation of blocks.
* Small files problem. Small file problem solutions
* What is rack and rack awareness? Data locality.
* How does name node mange meta data fsimage; editlogs, SecondaryNameNode
* Describe High Availability
* What are differences between CheckpointingNameNode and BackupNameNode?
* Namespaces and Federation
* Analyze the benefits and challenges of the HDFS architecture.
* File Formats. Describe and compare these file formats: ORC, Sequence; Avro; JSON
* HDFS VS S3 VS Azure Blob storage
* HDFS regarding CAP theorem