[id="tuned-profiles_{context}"]
= TuneD profiles

A detailed analysis of a system can be very time-consuming. *TuneD* provides a number of predefined profiles for typical use cases. You can also create, modify, and delete profiles.

The profiles provided with *TuneD* are divided into the following categories:

* Power-saving profiles
* Performance-boosting profiles

The performance-boosting profiles include profiles that focus on the following aspects:

* Low latency for storage and network
* High throughput for storage and network
* Virtual machine performance
* Virtualization host performance

[discrete]
== The default profile

During the installation, the best profile for your system is selected automatically. Currently, the default profile is selected according to the following customizable rules:

[options="header",cols="2,2,3"]
|===
| Environment | Default profile | Goal
| Compute nodes | `throughput-performance` | The best throughput performance
| Virtual machines | `virtual-guest` | The best performance. If you are not interested in the best performance, you can change it to the `balanced` or `powersave` profile.
| Other cases | `balanced` | Balanced performance and power consumption
|===


[discrete]
== Merged profiles

As an experimental feature, it is possible to select more profiles at once. *TuneD* will try to merge them during the load.

If there are conflicts, the settings from the last specified profile takes precedence.

.Low power consumption in a virtual guest
====
The following example optimizes the system to run in a virtual machine for the best performance and concurrently tunes it for low power consumption, while the low power consumption is the priority:

----
# tuned-adm profile virtual-guest powersave
----
====

WARNING: Merging is done automatically without checking whether the resulting combination of parameters makes sense. Consequently, the feature might tune some parameters the opposite way, which might be counterproductive: for example, setting the disk for high throughput by using the `throughput-performance` profile and concurrently setting the disk spindown to the low value by the `spindown-disk` profile.

[discrete]
== The location of profiles

*TuneD* stores profiles in the following directories:

[filename]`/usr/lib/tuned/`::
Distribution-specific profiles are stored in the  directory. Each profile has its own directory. The profile consists of the main configuration file called `tuned.conf`, and optionally other files, for example helper scripts.

[filename]`/etc/tuned/`::
If you need to customize a profile, copy the profile directory into the  directory, which is used for custom profiles. If there are two profiles of the same name, the custom profile located in [filename]`/etc/tuned/` is used.


[discrete]
== The syntax of profile configuration

The `tuned.conf` file can contain one `[main]` section and other sections for configuring plug-in instances. However, all sections are optional.

Lines starting with the hash sign (`#`) are comments.

.Additional resources

* The `tuned.conf(5)` man page.

