1. Local File System (LFS) :
The basic file system of Linux operating system is termed as Local file system. It stores any data file as it is in single copy.
It stores data files in Tree format. Here, any user can access data files directly. LFS does not Replicate the data blocks. It always used for storing and processing personal data(small data).
2. Distributed File System (DFS) :
When we need to store and process a large data file (approx 1 TB size file at least), the Local file system of Operating system is not appropriate. In such cases we use Distributed File system. It can be created on any Linux operating system with Hadoop. DFS stores any data file by dividing it into several blocks.
This file system works on Master-Slave format where Master is NameNode and DataNodes are the slaves. All the blocks of a Data file is stored into different DataNodes and the location is only known by NameNode. Every Data Block is replicated into different Datanodes to avoid data loss when any datanode fails. In DFS Data files are directly not accessible to any user because only NameNode knows where the Data blocks of Data file are stored.
Difference between Local File System (LFS) and Distributed File System (DFS) :
| Local File System | Distributed File System |
|---|---|
| LFS stores data as a single block. | DFS divides data as multiple blocks and stores it into different DataNodes. |
| LFS uses Tree format to store Data. | DFS provides Master-Slave architecture for Data storage. |
| Data retrieval in LFS is slow. | Data retrieval in DFS is fast. |
| It is not reliable because LFS data does not replicate the Data files. | It is reliable because in DFS data blocks are replicated into different DataNodes. |
| LFS is cheaper because it does not needs extra memory for storing any data file. | DFS is expensive because it needs extra memory to replicate the same data blocks. |
| Files can be accessed directly in LFS. | Files can not be accessed directly in DFS because the actual location of data blocks are only known by NameNode. |
| LFS is not appropriate for analysis of very big file of data because it needs large time to process. | DFS is appropriate for analysis of big file of data because it needs less amount of time to process as compare to Local file system. |
| LFS is less complex than DFS. | DFS is more complex than LFS. |