4. Operate Running Systems

📘Red Hat Certified System Administrator (RHCSA – EX200)

This section explains how to manage system performance tuning using tuning profiles in Red Hat Enterprise Linux. For the RHCSA (EX200) exam, you must understand how to view, select, and apply tuning profiles using the correct commands.

This topic mainly focuses on the TuneD service.

1. What is System Tuning?

System tuning means adjusting the system settings to improve performance based on how the server is used.

In an IT environment, different servers have different roles:

A database server needs high disk and memory performance.
A virtualization host needs CPU optimization.
A file server may need network tuning.
A development workstation may need balanced performance and power saving.

Instead of manually changing many configuration files, Red Hat provides a tool called TuneD that applies predefined tuning profiles.

2. What is TuneD?

TuneD is a system service in
Red Hat Enterprise Linux
that optimizes system performance automatically by applying tuning profiles.

It adjusts settings such as:

CPU governor
Disk I/O scheduler
Kernel parameters
Network settings
Power management options

TuneD uses profiles, and each profile is designed for a specific type of workload.

3. TuneD Service

The TuneD service runs in the background and applies the selected profile settings automatically.

The service name is:

tuned

3.1 Check TuneD Status

systemctl status tuned

For the exam, make sure the service is:

Installed
Running
Enabled at boot

3.2 Start and Enable TuneD

Start the service:

sudo systemctl start tuned

Enable it at boot:

sudo systemctl enable tuned

4. The tuned-adm Command

The main command used to manage tuning profiles is:

tuned-adm

You must know this command for the RHCSA exam.

5. Viewing Available Profiles

To see all available profiles:

tuned-adm list

Example output:

Available profiles:
- balanced
- throughput-performance
- latency-performance
- network-latency
- network-throughput
- powersave
- virtual-guest
- virtual-host
Current active profile: balanced

6. Check Current Active Profile

tuned-adm active

This shows which profile is currently applied.

7. Applying a Tuning Profile

To switch to a new profile:

sudo tuned-adm profile profile-name

Example:

sudo tuned-adm profile throughput-performance

After applying, verify:

tuned-adm active

8. Common Tuning Profiles (Important for Exam)

You should understand what each common profile is used for.

8.1 balanced (Default)

Default profile
Good balance between performance and power usage
Suitable for general-purpose servers

8.2 throughput-performance

Maximizes overall system throughput
Optimized for high data processing
Suitable for:
- Database servers
- High-load application servers
- Storage servers

8.3 latency-performance

Reduces latency (response time)
Prioritizes fast response over power saving
Suitable for:
- Real-time applications
- High-frequency transaction systems

8.4 network-throughput

Optimizes for high network data transfer
Suitable for:
- File servers
- Backup servers
- Large data transfer systems

8.5 network-latency

Reduces network response delay
Suitable for:
- Systems requiring fast network response
- Financial or API servers

8.6 powersave

Minimizes power usage
Reduces CPU frequency
Suitable for:
- Development systems
- Lab environments

8.7 virtual-guest

Optimized for virtual machines
Should be used inside VMs
Adjusts settings for hypervisor-based environments

8.8 virtual-host

Optimized for virtualization hosts
Suitable for systems running many VMs

9. Where Profiles Are Stored

Profiles are stored in:

/usr/lib/tuned/

Each profile has its own directory containing configuration files.

Custom profiles can be stored in:

/etc/tuned/

Important for exam:

You may need to copy and modify a profile.
Always place custom profiles in /etc/tuned/.

10. Creating a Custom Tuning Profile (Basic Concept)

Although RHCSA usually focuses on using profiles, you should understand the basics.

Steps:

Copy an existing profile: sudo cp -r /usr/lib/tuned/balanced /etc/tuned/myprofile
Edit: sudo vi /etc/tuned/myprofile/tuned.conf
Apply: sudo tuned-adm profile myprofile

11. Verify Profile Changes

After switching profiles, you can verify:

tuned-adm active

You can also check CPU governor:

cpupower frequency-info

(If cpupower is installed.)

12. Important Exam Points

For RHCSA (EX200), you must be able to:

✔ Check if TuneD is installed
✔ Start and enable tuned service
✔ List available profiles
✔ Identify current active profile
✔ Switch to a required profile
✔ Verify the change

You are usually NOT required to deeply edit kernel parameters manually.

13. Typical Exam Task Example

You may get a task like:

Configure the system to use the throughput-performance profile.
Ensure the configuration persists after reboot.

Steps:

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

Verify:

tuned-adm active

That is enough to pass this task.

14. Why Tuning Profiles Are Important in IT

In production IT environments:

A database server must handle thousands of queries per second.
A virtualization server must efficiently manage CPU and memory.
A backup server must transfer large files over the network.

Using the correct tuning profile ensures:

Better performance
Stable system behavior
Efficient resource usage
Reduced manual configuration errors

15. Quick Revision Summary (Must Remember)

Command	Purpose
`systemctl status tuned`	Check TuneD service
`systemctl start tuned`	Start service
`systemctl enable tuned`	Enable at boot
`tuned-adm list`	Show available profiles
`tuned-adm active`	Show current profile
`tuned-adm profile <name>`	Apply profile

Final Exam Strategy

For RHCSA:

Do not overthink.
Use tuned-adm correctly.
Always verify your changes.
Make sure the tuned service is enabled.
Confirm the active profile before finishing.

If you can confidently manage TuneD profiles using commands, you will successfully complete this exam objective.