What will you do if Nginx cannot handle a large…

I will check the Nginx configuration: parameters worker_processes, worker_connections, multi_accept, use (epoll/kqueue), and keepalive_requests, keepalive_timeout. I will increase them if necessary.

I will monitor system limits: ulimit -n for the Nginx process. I will increase it to the appropriate value.

I will optimize Linux kernel settings related to networking: net.core.somaxconn, net.ipv4.tcp_tw_reuse, net.ipv4.tcp_fin_timeout.

I will analyze Nginx logs (error_log, access_log) for errors or anomalies.

I will use monitoring tools (nginx-status, top, vmstat, iostat, netdata, Prometheus/Grafana) to identify bottlenecks (CPU, memory, disk, network).

I will consider using more powerful hardware or scaling (adding additional Nginx instances behind a load balancer).

I will check backend servers: the problem might not be with Nginx, but on the application side processing requests.

# Increase the number of worker processes
worker_processes auto;

# Increase the number of connections per worker
events {
    worker_connections 65536;
    multi_accept on;
    use epoll; # For Linux
}

http {
    # Keep-alive settings
    keepalive_requests 10000;
    keepalive_timeout 65;

    # ... other settings
}

# Check current limit for the Nginx user
su - nginx -c 'ulimit -n'

# Increase the limit in /etc/security/limits.conf
# nginx - nofile 65536
# nginx - nproc 65536

# Restart SSH session or server to apply limits.conf

# Check and modify kernel parameters
# Each change requires running sysctl -p
# sysctl net.core.somaxconn
# sysctl -w net.core.somaxconn=65536

# sysctl net.ipv4.tcp_tw_reuse
# sysctl -w net.ipv4.tcp_tw_reuse=1

# sysctl net.ipv4.tcp_fin_timeout
# sysctl -w net.ipv4.tcp_fin_timeout=30

What will you do if Nginx cannot handle a large number of connections (more than 1024)?