The Google File System (GFS) is a distributed file system that is designed to provide scalable and fault-tolerant storage for large data sets. It is used extensively within Google and is the foundation of many of Google's cloud-based services.
The architecture of GFS is based on a master-slave design, where a single master node coordinates the actions of multiple slave nodes that store and retrieve data. The master node is responsible for managing the file system namespace, allocating and replicating data across the slave nodes, and balancing the workload across the system.
The slave nodes are commodity hardware machines that are connected via a high-speed network. Each slave node runs a GFS daemon process, which manages the storage and retrieval of data from its local disk. The data is stored in fixed-size chunks of 64 MB, which are replicated across multiple slave nodes to provide fault tolerance and data redundancy.
The client applications interact with the GFS using a client library that provides a file system interface similar to that of a traditional file system. The client library communicates with the master node to perform operations such as opening files, reading and writing data, and closing files.
GFS uses a number of techniques to ensure high performance and reliability. For example, it employs a distributed caching system to cache frequently accessed data in memory on the slave nodes. It also uses a technique called lazy replication, where data is replicated only when it is needed, to reduce the overhead of replication.
Overall, the architecture of GFS is designed to provide a scalable and fault-tolerant file system that can handle large data sets in a distributed environment.
