Siege - HTTP Load Testing and Benchmarking Tool Guide

Table of Contents

• Overview
• Installation
• Basic Usage
• Advanced Options
• Configuration
• Statistics Analysis
• Load Testing Strategies
• Best Practices

Overview

Siege is a multi-threaded HTTP load testing and benchmarking utility designed to let web developers measure their code under duress.

Key Features

• Concurrent user simulation
• URL file support
• HTTP/HTTPS testing
• Cookie support
• Basic authentication
• POST/PUT data support
• Detailed statistics
• Configuration file support

Installation

Ubuntu (22.04/24.04)

# Install siege
sudo apt update
sudo apt install siege
 
# Verify installation
siege --version

macOS

# Using Homebrew
brew install siege

Basic Usage

Simple Tests

# Basic test (default 15 seconds)
siege http://localhost/
 
# Specify concurrent users
siege -c 25 http://localhost/
 
# Set duration
siege -t 30S http://localhost/
 
# Specify number of repetitions
siege -r 100 http://localhost/

Basic Options

# Verbose output
siege -v http://localhost/
 
# Quiet mode
siege -q http://localhost/
 
# Internet mode (random delay)
siege -i http://localhost/

Advanced Options

Authentication and Headers

# Basic authentication
siege --auth=username:password http://localhost/
 
# Add header
siege --header="X-Custom-Header: Value" http://localhost/
 
# Multiple headers
siege --header="Authorization: Bearer token" \
      --header="Content-Type: application/json" \
      http://localhost/

POST Requests

# POST with data
siege --content-type="application/json" \
      --data='{"key":"value"}' \
      http://localhost/api
 
# POST from file
siege --content-type="application/json" \
      --data-file=payload.json \
      http://localhost/api

Configuration

Siege Configuration File

# View current config
siege.config
 
# Default location: ~/.siegerc

Sample Configuration

# .siegerc
verbose = true
quiet = false
color = on
protocol = HTTP/1.1
connection = keep-alive
concurrent = 25
time = 30S
internet = false
delay = 1
timeout = 30
parser = true
cache = false
header = Content-Type: application/json
header = X-Custom-Header: Value

URL File Usage

# Create URL file
cat > urls.txt << EOF
http://localhost/page1
http://localhost/page2
POST http://localhost/api data=value
EOF
 
# Run with URL file
siege -f urls.txt

Statistics Analysis

Understanding Output

Transactions:                   1000 hits
Availability:                 100.00 %
Elapsed time:                  59.99 secs
Data transferred:              1.23 MB
Response time:                 0.15 secs
Transaction rate:             16.67 trans/sec
Throughput:                    0.02 MB/sec
Concurrency:                   2.50
Successful transactions:       1000
Failed transactions:              0
Longest transaction:           1.23
Shortest transaction:          0.01

Logging Options

# Enable logging
siege --log=/path/to/siege.log http://localhost/
 
# Log format
siege --mark="Test 1" http://localhost/
 
# JSON output
siege --json http://localhost/

Load Testing Strategies

Progressive Load Testing

#!/bin/bash
# Increase load progressively
for c in 10 25 50 100; do
    echo "Testing with $c concurrent users"
    siege -c $c -t 30S http://localhost/
    sleep 10
done

Extended Duration Tests

# Long-running test
siege -c 50 -t 1H http://localhost/
 
# With delay between requests
siege -c 50 -d 1 -t 1H http://localhost/

Mixed Request Testing

# Create mixed request file
cat > mixed.txt << EOF
GET http://localhost/api/users
POST http://localhost/api/data {"id":1}
GET http://localhost/api/status
EOF
 
siege -f mixed.txt -c 25 -t 30S

Best Practices

Testing Guidelines

# Warm-up run
siege -c 1 -t 10S http://localhost/
 
# Progressive testing
siege -c 10 -t 1M http://localhost/
siege -c 25 -t 1M http://localhost/
siege -c 50 -t 1M http://localhost/

Resource Monitoring

# Monitor system resources
while true; do
    date
    uptime
    netstat -an | grep ESTABLISHED | wc -l
    sleep 5
done

Quick Reference

Essential Commands

# Basic test
siege http://localhost/
 
# Concurrent users and time
siege -c 25 -t 30S http://localhost/
 
# URL file test
siege -f urls.txt
 
# Internet simulation
siege -i -c 25 -t 30S http://localhost/

Common Options

-c    # Concurrent users
-t    # Time duration
-r    # Number of repetitions
-d    # Delay between requests
-f    # URL file
-i    # Internet simulation
-v    # Verbose output
-q    # Quiet mode

Example Configurations

API Load Test

#!/bin/bash
# API endpoint testing
siege -c 25 \
      --content-type="application/json" \
      --header="Authorization: Bearer token" \
      -t 5M \
      http://localhost/api

Web Application Test

#!/bin/bash
# Create URL list
cat > urls.txt << EOF
http://localhost/
http://localhost/login
http://localhost/dashboard
http://localhost/api/status
EOF
 
# Run test with delays
siege -f urls.txt -c 50 -d 1 -t 30M

Performance Benchmark

#!/bin/bash
# Full benchmark suite
ENDPOINTS=(
    "http://localhost/api/v1"
    "http://localhost/api/v2"
)
 
for endpoint in "${ENDPOINTS[@]}"; do
    echo "Testing $endpoint"
    siege -c 25 -t 1M "$endpoint"
    sleep 5
done

---

Remember:

• Start with low concurrency
• Monitor server resources
• Use appropriate delays
• Consider internet simulation for realism
• Log results for analysis
• Watch for error rates

For detailed information, consult the siege man page (man siege).