Bob Digs into System Performance Tuning on AlmaLinux

Bob Digs into System Performance Tuning, where Bob learns how to monitor and optimize his AlmaLinux system to keep it running smoothly and efficiently.

1. Introduction: Bob’s Performance Challenge

Bob’s system has been slowing down recently, especially during heavy tasks. Eager to understand why, he decides to explore system performance monitoring and tuning. This will allow him to identify resource hogs and optimize his setup for peak performance.

“Time to get to the bottom of what’s slowing things down!” Bob says, ready for his next learning adventure.

2. Identifying Bottlenecks with top, htop, and iostat

Bob starts by reviewing basic performance metrics to get a snapshot of system health. He focuses on CPU, memory, and disk I/O usage.

• Using top for a Quick Overview: Bob runs:

  top
  

  This shows real-time CPU and memory usage per process. He identifies processes that are using the most resources and notices that a few background tasks are consuming too much CPU.

• Switching to htop for More Details: To view a more detailed, interactive interface, Bob uses htop, which provides color-coded bars and an organized layout:

  htop
  

  He sorts by CPU and memory to quickly identify resource-heavy processes.

• Checking Disk I/O with iostat: Disk performance issues can also slow down a system. To monitor disk activity, Bob uses iostat, which is part of the sysstat package:

  sudo dnf install sysstat
  iostat -x 2
  

  This command shows per-disk statistics, allowing Bob to identify any disk that’s overworked or has high wait times.

“Now I can pinpoint which processes and disks are slowing things down!” Bob says, armed with insights.

3. Optimizing CPU and Memory Usage

Bob notices some processes are consuming more CPU and memory than they should. He decides to tweak his system settings to control resource usage and improve performance.

• Limiting Process Resources with ulimit: Bob uses ulimit to set limits on CPU and memory usage for specific processes:

  ulimit -u 100  # Limits the number of processes a user can start
  

  This prevents any single user or application from hogging system resources.

• Adjusting sysctl Parameters: For more control, Bob uses sysctl to modify system parameters. For example, he adjusts swappiness (the kernel’s tendency to swap memory) to reduce unnecessary swapping:

  sudo sysctl vm.swappiness=10
  

  Lowering swappiness makes his system prefer RAM over swap space, which improves performance when memory usage is high.

“A few tweaks make a big difference in resource usage!” Bob notes, pleased with his improvements.

4. Managing Disk I/O and Caching

Disk I/O can slow things down, especially when multiple processes compete for disk access. Bob dives into optimizing disk performance to ensure smoother operation.

• Monitoring with iostat and iotop: Bob uses iotop to monitor I/O activity by process. This helps him find specific processes causing high disk usage:

  sudo iotop
  

• Tuning Disk Caching with sysctl: To enhance performance, he adjusts disk caching parameters. For instance, increasing read-ahead improves sequential read performance:

  sudo sysctl -w vm.dirty_background_ratio=10
  sudo sysctl -w vm.dirty_ratio=20
  

  These values control when data gets written from cache to disk, reducing disk load and improving responsiveness.

“Managing disk I/O really smooths things out!” Bob observes, noticing his system responds faster.

5. Optimizing File Descriptor and Process Limits

Bob learns that systems can hit limits on file descriptors or processes, causing errors or delays. By adjusting these limits, he ensures that his system can handle high demand.

• Increasing File Descriptors: File descriptors manage open files, and too few can lead to bottlenecks. Bob increases the limit by adding a line in /etc/sysctl.conf:

  fs.file-max = 100000
  

  After saving, he applies the change with:

  sudo sysctl -p
  

• Setting Process Limits with limits.conf: Bob edits /etc/security/limits.conf to set maximum processes per user:

  bob soft nproc 2048
  bob hard nproc 4096
  

  This ensures his account has sufficient resources without overwhelming the system.

“Adjusting limits makes sure my system can handle the load during peak times,” Bob notes, feeling more confident about system stability.

6. Fine-Tuning System with tuned

Bob discovers that AlmaLinux includes tuned, a dynamic tuning service that optimizes settings based on various profiles, like “throughput-performance” for servers or “powersave” for laptops.

• Installing tuned: If it’s not installed, he adds it with:

  sudo dnf install tuned
  

• Choosing a Profile: Bob starts tuned and selects a profile for his setup:

  sudo systemctl start tuned
  sudo tuned-adm profile throughput-performance
  

  This profile configures the system for maximum throughput, optimizing network and disk performance.

“With tuned, I can switch between profiles without manually adjusting settings!” Bob says, grateful for the simplicity.

7. Monitoring and Logging with dstat and vmstat

To track long-term system performance, Bob sets up dstat and vmstat to monitor CPU, memory, disk, and network usage.

• Using dstat for Live Stats: Bob installs and runs dstat, which combines multiple performance metrics into one view:

  sudo dnf install dstat
  dstat
  

• Tracking Memory and CPU with vmstat: For a snapshot of CPU and memory performance, he uses vmstat:

  vmstat 5
  

  This command updates every 5 seconds, showing Bob trends in memory usage and CPU load.

“These tools give me a full picture of what’s going on over time,” Bob says, happy to have long-term visibility.

8. Conclusion: Bob’s System Runs Smoothly

After fine-tuning his system, Bob notices a clear improvement in performance. His CPU, memory, and disk I/O are optimized, and he has tools in place to track performance over time. Bob feels accomplished—he’s learned to tune AlmaLinux for efficiency and responsiveness.

Next up, Bob wants to explore user management and system auditing to keep his system organized and secure.

Stay tuned for the next chapter: “Bob’s Guide to User Management and System Auditing!”