Hadoop Storage ( HDFS)

HDFS (Hadoop Distributed File System) is a fundamental component of the Apache Hadoop ecosystem designed specifically for handling big data processing. It provides a distributed storage system that can reliably store massive amounts of data across clusters of commodity hardware.

Key Characteristics of HDFS

• Write-Once, Read-Many (WORM): HDFS is optimized for write-once, read-many operations, meaning files are written once and read multiple times
• Distributed Storage: Breaks large files into smaller blocks and distributes them across multiple nodes in a cluster
• Fault Tolerance: Maintains multiple copies of data blocks across different nodes to ensure data reliability and availability
• High Throughput: Optimized for large data sets and batch processing rather than interactive use
• Scalability: Can easily scale horizontally by adding more nodes to the cluster

Architecture Components

• NameNode: Manages the file system namespace and regulates access to files
• DataNodes: Store actual data blocks and handle read/write requests from clients

HDFS is particularly well-suited for applications that require processing large datasets in parallel, making it an essential tool in modern big data analytics and processing workflows.

graph TD;
    A["Client File"] --> B["HDFS Client"];
    B --> C["Split into Blocks"];
    
    C --> D["Block A"];
    C --> E["Block B"];
    C --> F["Block C"];
    
    subgraph NameNode[NameNode System]
        style NameNode fill:#e6f3ff,stroke:#4d94ff
        G1["Metadata"]
        G2["Block Locations"]
    end
    
    D --> NameNode;
    E --> NameNode;
    F --> NameNode;
    
    NameNode --> H["DataNode 1"];
    NameNode --> I["DataNode 2"];
    NameNode --> J["DataNode 3"];
    
    %% Block A Replication
    D --> K["Block A Copy 1<br/>DataNode 1"];
    D --> L["Block A Copy 2<br/>DataNode 2"];
    D --> M["Block A Copy 3<br/>DataNode 3"];
    
    %% Block B Replication
    E --> N["Block B Copy 1<br/>DataNode 2"];
    E --> O["Block B Copy 2<br/>DataNode 3"];
    E --> P["Block B Copy 3<br/>DataNode 1"];
    
    %% Block C Replication
    F --> Q["Block C Copy 1<br/>DataNode 3"];
    F --> R["Block C Copy 2<br/>DataNode 1"];
    F --> S["Block C Copy 3<br/>DataNode 2"];

 

The diagram shows:

1. Client file submission to HDFS
2. File splitting into Blocks A, B, and C
3. Each block is replicated 3 times
4. Block copies are distributed across different DataNodes for redundancy
5. NameNode manages the metadata and block locations