Understanding HDFS File System
What is HDFS?
HDFS (Hadoop Distributed File System) is the primary storage system used by Apache Hadoop applications. It is designed to store and process large datasets in a distributed computing environment. HDFS is highly fault-tolerant and is designed to run on commodity hardware, providing high-throughput access to application data.
Key Features of HDFS
- Scalability: HDFS can scale to hundreds of nodes in a single cluster, allowing it to handle large amounts of data.
- Fault Tolerance: HDFS automatically replicates data across multiple nodes, ensuring data availability even in the event of hardware failures.
- High Throughput: HDFS is optimized for high-throughput access to application data, making it suitable for batch processing workloads.
- Cost-Effective: HDFS runs on commodity hardware, making it a cost-effective storage solution for large-scale data processing.
HDFS Architecture
HDFS follows a master-slave architecture, consisting of the following components:
graph TD
NameNode -- Manages file system metadata --> DataNode
DataNode -- Stores and processes data --> NameNode
- NameNode: The NameNode is the master node that manages the file system namespace and controls access to files by clients.
- DataNode: The DataNodes are the worker nodes that store the actual data and perform data operations, such as reading, writing, and replicating data blocks.
HDFS File System Operations
HDFS provides a set of command-line tools for interacting with the file system. Some of the commonly used HDFS commands include:
hdfs dfs -ls
: List the contents of a directory.
hdfs dfs -put
: Copy files from the local file system to HDFS.
hdfs dfs -get
: Copy files from HDFS to the local file system.
hdfs dfs -mkdir
: Create a new directory.
hdfs dfs -rm
: Remove a file or directory.
Understanding these basic HDFS commands is crucial for working with the Hadoop ecosystem.