Advanced Linux Topics

Kernel tuning is essential for optimizing system performance. Key parameters can be adjusted via the `/proc/sys` interface.

Key Parameters

• vm.swappiness: Controls the tendency of the kernel to move processes out of physical memory and onto the swap disk.
• fs.file-max: The maximum number of file handles that the kernel will allocate.
• net.ipv4.tcp_max_syn_backlog: The maximum number of connection requests that can be queued for acceptance.

Example: Adjusting Swappiness

echo 10 > /proc/sys/vm/swappiness

To make changes persistent, edit /etc/sysctl.conf:

vm.swappiness=10

Linux supports a wide range of networking configurations. Advanced topics include:

• IP Tables for firewall management.
• Bridging and bonding for network redundancy.
• Network namespaces for isolated network environments.

Example: Setting Up a Basic Firewall

iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT

Security in Linux is multi-faceted, involving user permissions, SELinux, and auditing.

Best Practices

• Use sudo for privilege escalation.
• Implement SELinux or AppArmor for access control.
• Regularly update the system and applications.

Monitoring system performance is crucial for maintaining optimal operations. Tools include:

• top and htop for process monitoring.
• vmstat for memory statistics.
• iostat for disk I/O statistics.

Example: Checking Disk I/O

iostat -x 1 10

Shell scripting automates repetitive tasks. Basic structure includes:

#!/bin/bash
echo "Hello, World!"

Best Practices

• Use comments to document your code.
• Check exit status of commands.
• Use variables for dynamic values.