Distributed File System

A distributed file system implementation using C programming and socket communication, designed for educational purposes and demonstrating basic distributed computing concepts.

System Architecture

The system consists of 4 servers and 1 client that work together to provide a distributed file storage solution:

• S1 (Main Server): Primary server that handles client connections and coordinates file distribution
• S2 (PDF Server): Dedicated server for storing PDF files
• S3 (Text Server): Dedicated server for storing text files
• S4 (ZIP Server): Dedicated server for storing ZIP files
• s25client: Client application for user interaction

File Distribution Logic

Files are automatically distributed based on their extensions:

File Type	Extension	Storage Location
C Source Files	.c	S1 (Main Server)
PDF Documents	.pdf	S2 (PDF Server)
Text Files	.txt	S3 (Text Server)
ZIP Archives	.zip	S4 (ZIP Server)

Features

• Multi-client Support: S1 uses fork() to handle multiple concurrent client connections
• Automatic File Distribution: Files are automatically routed to appropriate servers
• Transparent Access: Clients interact only with S1, unaware of the distributed nature
• File Operations: Upload, download, delete, and list files across the distributed system
• Tar Archive Creation: Create compressed archives of specific file types
• Directory Management: Automatic creation of directory structures

Prerequisites

• Operating System: Linux/Unix environment
• Compiler: GCC with C99 support
• Network: All servers and client must be able to communicate via sockets
• Permissions: Write access to home directory for creating server directories

Installation

1. Clone the repository:

   git clone <repository-url>
   cd DistributedFileSystem

2. Compile the project:

   make all

3. Create required directories:

   make install

Usage

Starting the Servers

Start each server in separate terminals:

# Terminal 1 - Main Server (S1)
./S1

# Terminal 2 - PDF Server (S2)
./S2

# Terminal 3 - Text Server (S3)
./S3

# Terminal 4 - ZIP Server (S4)
./S4

Running the Client

# Terminal 5 - Client
./s25client

Available Commands

1. Upload Files (uploadf)

Upload up to 3 files to the distributed system:

uploadf file1.c file2.pdf file3.txt ~S1/destination/path

2. Download Files (downlf)

Download up to 2 files from the system:

downlf ~S1/path/file1.c ~S1/path/file2.pdf

3. Remove Files (removef)

Delete up to 2 files from the system:

removef ~S1/path/file1.c ~S1/path/file2.pdf

4. Download Tar Archive (downltar)

Create and download a tar archive of specific file type:

downltar .c    # Downloads cfiles.tar
downltar .pdf  # Downloads pdf.tar
downltar .txt  # Downloads text.tar

5. Display File Names (dispfnames)

List all files in a directory:

dispfnames ~S1/directory/path

Configuration

Port Configuration

• S1 (Main Server): Port 8080
• S2 (PDF Server): Port 8081
• S3 (Text Server): Port 8082
• S4 (ZIP Server): Port 8083

Directory Structure

~/S1/          # Main server files (.c files)
~/S2/          # PDF server files
~/S3/          # Text server files
~/S4/          # ZIP server files

Testing

1. Start all servers in separate terminals
2. Run the client and test each command
3. Verify file distribution by checking the appropriate server directories
4. Test concurrent connections by running multiple clients

Example Test Sequence

# Upload files
uploadf sample.c document.pdf readme.txt ~S1/test/

# List files
dispfnames ~S1/test/

# Download files
downlf ~S1/test/sample.c ~S1/test/document.pdf

# Create tar archive
downltar .c

# Remove files
removef ~S1/test/sample.c

Project Structure

DistributedFileSystem/
├── S1.c              # Main server implementation
├── S2.c              # PDF server implementation
├── S3.c              # Text server implementation
├── S4.c              # ZIP server implementation
├── s25client.c       # Client application
├── Makefile          # Build configuration
└── README.md         # This file

Technical Details

Socket Communication

• Protocol: TCP sockets
• Address: 127.0.0.1 (localhost)
• Communication: Bidirectional client-server communication

Process Management

• Forking: S1 forks child processes for each client connection
• Process Isolation: Each client connection runs in its own process
• Signal Handling: Proper cleanup of child processes

File Operations

• Binary Transfer: Files are transferred in binary mode
• Chunked Transfer: Large files are transferred in chunks
• Error Handling: Basic error checking and validation

Troubleshooting

Common Issues

1. Port Already in Use:

   # Check if ports are in use
   netstat -tulpn | grep :808
   
   # Kill processes using the ports
   sudo kill -9 <PID>

2. Permission Denied:

   # Make sure directories are writable
   chmod 755 ~/S1 ~/S2 ~/S3 ~/S4

3. Connection Refused:

   • Ensure all servers are running
   • Check firewall settings
   • Verify port availability

Debug Mode

Compile with debug flags for detailed output:

make debug

Educational Value

This project demonstrates:

• Socket Programming: Network communication between processes
• Process Management: Forking and child process handling
• File System Operations: File I/O and directory management
• Distributed Systems: Basic concepts of distributed file storage
• C Programming: System programming and network protocols

Acknowledgments

• Inspired by distributed systems concepts
• Built for educational purposes
• Uses standard C libraries and system calls

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Note: This is an educational project designed to demonstrate basic distributed computing concepts. For production use, additional security, error handling, and performance optimizations would be required.