Resource Limiting Skill

Protect shared servers from resource exhaustion during development tasks.

When to Use

•Running tests on a server that hosts other sites
•Running migrations on a shared database server
•Running any CPU/RAM intensive task on production/staging
•When you notice server becoming unresponsive during tasks

The Problem

Development tasks like tests, builds, and migrations can consume 100% CPU/RAM, causing:

•Other websites on the server to stop responding
•SSH connections to hang
•Database connections to time out
•Server to become unreachable until task finishes

Solution: Resource Limiting

Quick Commands

For tests (recommended):

bash

nice -n 19 ionice -c 3 vendor/bin/pest --processes=1
nice -n 19 ionice -c 3 npm test
nice -n 19 ionice -c 3 pytest

For any heavy command:

bash

nice -n 19 ionice -c 3 <your-command>

Tools

Tool	Built-in?	What it Does
`nice -n 19`	Yes	Lowest CPU priority - other processes get CPU first
`ionice -c 3`	Yes	Lowest I/O priority - other processes get disk first
`cpulimit -l 50`	No	Hard limit to 50% CPU (install: `apt install cpulimit`)
`--processes=1`	N/A	Disable parallel testing

By Task Type

Running Tests

bash

# Best for shared servers
nice -n 19 ionice -c 3 vendor/bin/pest --processes=1

# If you have cpulimit installed
cpulimit -l 50 -- vendor/bin/pest

Running Migrations

bash

nice -n 19 php artisan migrate
nice -n 19 python manage.py migrate

Running Builds

bash

nice -n 19 npm run build
nice -n 19 composer install

Running Heavy Scripts

bash

nice -n 19 ionice -c 3 php artisan queue:work --once

Advanced: systemd Resource Control

For Linux servers with systemd:

bash

# Limit to 50% CPU and 1GB RAM
systemd-run --scope -p CPUQuota=50% -p MemoryMax=1G vendor/bin/pest

# Limit to 25% CPU and 512MB RAM
systemd-run --scope -p CPUQuota=25% -p MemoryMax=512M npm test

Detection: Is This a Shared Server?

bash

# Check for web servers
pgrep nginx && echo "Nginx running - shared server likely"
pgrep apache2 && echo "Apache running - shared server likely"
pgrep mysql && echo "MySQL running - shared server likely"

# Check for other PHP processes
pgrep -c php-fpm && echo "PHP-FPM running - shared server"

Rule: If web servers are running, use resource limits.

Checklist

Before running heavy tasks on shared servers:

• Check if this is a shared/production server
• Use nice -n 19 for CPU priority
• Use ionice -c 3 for disk I/O priority
• Use --processes=1 to disable parallel execution
• Consider running in CI/CD instead of on server

Best Practice

Add to your project's CLAUDE.md:

markdown

## Server Environment

This is a shared server hosting multiple sites.
ALWAYS use resource limits when running tests or heavy tasks:

```bash
nice -n 19 ionice -c 3 vendor/bin/pest --processes=1

code


## Related Skills

- `database-backup` - Backup before heavy operations
- `defense-in-depth` - Multiple safety layers