Linux Performance Tuning Guide

1. System Monitoring

Before optimizing, it's crucial to understand your system's current performance. Use these tools to monitor various aspects of your Linux server:

top or htop : Monitor real-time system statistics
vmstat : Report virtual memory statistics
iostat : Report CPU and I/O statistics
netstat : Monitor network connections and statistics
sar : Collect, report, and save system activity information

Tip: Use these tools regularly to establish baseline performance metrics and identify bottlenecks.

2. CPU Optimization

2.1 CPU Governor

The CPU governor controls the CPU frequency scaling. To view current governor:

cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

To set the performance governor:

echo performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

2.2 Process Niceness

Adjust process priority using the nice command. Lower values indicate higher priority:

nice -n -20 ./high_priority_process nice -n 19 ./low_priority_process

3. Memory Management

3.1 Swappiness

Reduce swappiness to minimize swap usage:

echo 10 | sudo tee /proc/sys/vm/swappiness

3.2 Transparent Huge Pages

Disable Transparent Huge Pages for database workloads:

echo never | sudo tee /sys/kernel/mm/transparent_hugepage/enabled

3.3 Virtual Memory Overcommit

Adjust VM overcommit settings:

echo 0 | sudo tee /proc/sys/vm/overcommit_memory

4. Disk I/O Optimization

4.1 I/O Scheduler

Choose an appropriate I/O scheduler. For SSDs, use 'noop' or 'deadline':

echo noop | sudo tee /sys/block/sda/queue/scheduler

4.2 Readahead

Adjust readahead settings:

sudo blockdev --setra 256 /dev/sda

4.3 Noatime Mount Option

Use the 'noatime' mount option in /etc/fstab to reduce disk writes.

5. Network Tuning

5.1 TCP Settings

Optimize TCP settings in /etc/sysctl.conf :

net.ipv4.tcp_fin_timeout = 30
net.ipv4.tcp_keepalive_time = 1200
net.ipv4.tcp_max_syn_backlog = 8192
net.ipv4.tcp_tw_reuse = 1

5.2 Network Interface

Increase network interface buffers:

sudo ethtool -G eth0 rx 4096 tx 4096

6. File System Optimization

6.1 Journaling

For ext4, consider disabling journaling for high-write scenarios:

sudo tune2fs -O ^has_journal /dev/sda1

6.2 TRIM (for SSDs)

Enable TRIM for SSDs:

sudo systemctl enable fstrim.timer

7. Application-Specific Tuning

Application	Tuning Tips
Web Server (Nginx/Apache)	Increase worker processes/threads Enable caching Optimize keepalive settings
Database (MySQL/PostgreSQL)	Adjust buffer pool size Optimize query cache Tune innodb_flush_method
Java Applications	Optimize JVM heap size Choose appropriate garbage collector Use JIT compiler optimizations