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R2R Troubleshooting Guide: Insufficient System Resources

When running R2R in Docker, you may encounter issues related to insufficient system resources. This guide will help you identify, diagnose, and resolve these problems.

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Symptoms of Insufficient Resources

1. Docker containers fail to start or crash unexpectedly
2. Slow performance or unresponsiveness of R2R services
3. Error messages related to memory, CPU, or disk space
4. Unexpected termination of processes within containers

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Diagnosing Resource Issues

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1. Check Docker Resource Usage

Use the following command to view resource usage for all containers:

docker stats

Look for containers using high percentages of CPU or memory.

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2. Check Host System Resources

On Linux:

top
free -h
df -h

On macOS:

top
vm_stat
df -h

On Windows:

Task Manager > Performance tab

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3. Review Docker Logs

Check logs for specific containers:

docker logs <container_name>

Look for out-of-memory errors or other resource-related messages.

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Common Issues and Solutions

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1. Insufficient Memory

Symptom: Containers crash with out-of-memory errors.

Solutions: a. Increase Docker’s memory limit:

• On Docker Desktop, go to Settings > Resources > Advanced and increase memory allocation.

b. Optimize memory usage in R2R configuration:

• Adjust NEO4J_server_memory_heap_max__size for Neo4j
• Modify Postgres memory settings in postgresql.conf

c. Add or increase swap space on your host system.

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2. CPU Constraints

Symptom: Slow performance or high CPU usage warnings.

Solutions: a. Increase Docker’s CPU limit:

• On Docker Desktop, go to Settings > Resources > Advanced and increase CPU allocation.

b. Optimize R2R and dependent services:

• Adjust thread pool sizes in configurations
• Consider using CPU-specific Docker options like --cpus or --cpu-shares

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3. Disk Space Issues

Symptom: “No space left on device” errors or containers failing to write data.

Solutions: a. Clean up Docker resources:

docker system prune

b. Increase disk space allocation for Docker:

• On Docker Desktop, go to Settings > Resources > Advanced and increase disk image size.

c. Monitor and manage log file sizes:

• Implement log rotation for services like Neo4j and Postgres
• Use Docker’s logging options to limit log file sizes:

  logging:
    options:
      max-size: "10m"
      max-file: "3"
  

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4. Network Resource Constraints

Symptom: Connection timeouts or network-related errors.

Solutions: a. Check and increase ulimit for open files:

ulimit -n 65535

b. Optimize Docker network settings:

• Use host network mode for better performance (if security allows)
• Adjust MTU settings if necessary

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Preventive Measures

1. Regular Monitoring: Set up monitoring tools like Prometheus and Grafana to track resource usage over time.

2. Resource Limits: Set appropriate resource limits in your Docker Compose file:

   services:
     r2r:
       deploy:
         resources:
           limits:
             cpus: '0.50'
             memory: 512M
           reservations:
             cpus: '0.25'
             memory: 256M
   

3. Performance Testing: Conduct regular performance tests to identify resource bottlenecks before they become critical.

4. Scaling Strategy: Develop a strategy for horizontal scaling of R2R services as your usage grows.

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When to Upgrade Hardware

Consider upgrading your hardware or moving to a more powerful cloud instance if:

1. You consistently hit resource limits despite optimization efforts.
2. Performance degrades as your data or user base grows.
3. You need to scale beyond what your current hardware can support.

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Seeking Further Help

If you’ve tried these solutions and still face resource issues:

1. Gather detailed logs and resource usage data.
2. Check the R2R documentation for specific resource recommendations.
3. Consult the R2R community forums or support channels.
4. Consider reaching out to a DevOps or Docker specialist for advanced troubleshooting.

Remember, optimal resource allocation often requires iterative testing and adjustment based on your specific use case and workload.