What are the key NGINX settings to avoid 502-504 errors during high traffic

1. Worker Processes and Connections:
- `worker_processes`: Ensure the optimal number of worker processes matches the number of CPU cores. For high traffic, set `worker_processes` to `auto` to allow NGINX to automatically determine the optimal value[1][2][5].
- `worker_connections`: Increase the maximum number of connections each worker process can handle simultaneously. For high traffic, set `worker_connections` to a higher value like 4096[1][2][5].

2. Timeouts and Idle Times:
- `keepalive_timeout`: Set this to a value close to your average response time to ensure keep-alive connections are utilized efficiently. For high traffic, set `keepalive_timeout` to a lower value like 10 seconds[1][2][5].
- `client_header_timeout`: Set this to a value that balances client request header processing with server resource utilization. For high traffic, set `client_header_timeout` to a lower value like 10 seconds[1][2][5].

3. FastCGI Settings:
- `fastcgi_buffer_size`, `fastcgi_buffers`, `fastcgi_busy_buffers_size`, and `fastcgi_temp_file_write_size`: Fine-tune these settings to optimize PHP processing and reduce the likelihood of 502 errors[3][5].

4. Caching and Compression:
- `gzip on`: Enable gzip compression to reduce bandwidth usage and improve page load times[3][5].
- `open_file_cache` and related settings: Implement caching for periodically accessed files to reduce server load and latency[5].

5. Monitoring and Troubleshooting:
- Regularly monitor access logs to identify performance bottlenecks and troubleshoot issues[4][5].

By optimizing these settings, you can minimize the likelihood of 502-504 errors during high traffic and ensure your NGINX server handles requests efficiently.