124 lines
3.9 KiB
Text
124 lines
3.9 KiB
Text
:_module-type: PROCEDURE
|
|
[id="setting-the-disk-scheduler-using-tuned_{context}"]
|
|
= Setting the disk scheduler using TuneD
|
|
|
|
[role="_abstract"]
|
|
This procedure creates and enables a *TuneD* profile that sets a given disk scheduler for selected block devices. The setting persists across system reboots.
|
|
|
|
In the following commands and configuration, replace:
|
|
|
|
* [replaceable]_device_ with the name of the block device, for example `sdf`
|
|
* [replaceable]_selected-scheduler_ with the disk scheduler that you want to set for the device, for example `bfq`
|
|
|
|
.Prerequisites
|
|
|
|
ifndef::pantheonenv[]
|
|
* The `tuned` service is installed and enabled. For details, see xref:installing-and-enabling-tuned_getting-started-with-tuned[Installing and enabling Tuned]
|
|
endif::[]
|
|
ifdef::pantheonenv[]
|
|
* The `tuned` service is installed and enabled. For details, see xref:modules/performance/proc_installing-and-enabling-tuned.adoc[Installing and enabling Tuned]
|
|
endif::[]
|
|
|
|
.Procedure
|
|
|
|
ifndef::pantheonenv[]
|
|
. Optional: Select an existing *TuneD* profile on which your profile will be based. For a list of available profiles, see xref:tuned-profiles-distributed-with-rhel_getting-started-with-tuned[Tuned profiles distributed with RHEL].
|
|
endif::[]
|
|
ifdef::pantheonenv[]
|
|
. Optional: Select an existing *TuneD* profile on which your profile will be based. For a list of available profiles, see xref:modules/performance/ref_tuned-profiles-distributed-with-rhel.adoc[Tuned profiles distributed with RHEL].
|
|
endif::[]
|
|
+
|
|
To see which profile is currently active, use:
|
|
+
|
|
----
|
|
$ tuned-adm active
|
|
----
|
|
|
|
. Create a new directory to hold your *TuneD* profile:
|
|
+
|
|
[subs="attributes, quotes"]
|
|
----
|
|
# mkdir {user-profile-dir}/[replaceable]__my-profile__
|
|
----
|
|
|
|
. Find the system unique identifier of the selected block device:
|
|
+
|
|
[subs="quotes"]
|
|
----
|
|
$ udevadm info --query=property --name=/dev/_device_ | grep -E '(WWN|SERIAL)'
|
|
|
|
ID_WWN=_0x5002538d00000000__
|
|
ID_SERIAL=_Generic-_SD_MMC_20120501030900000-0:0_
|
|
ID_SERIAL_SHORT=_20120501030900000_
|
|
----
|
|
+
|
|
[NOTE]
|
|
====
|
|
The command in the this example will return all values identified as a World Wide Name (WWN) or serial number associated with the specified block device. Although it is preferred to use a WWN, the WWN is not always available for a given device and any values returned by the example command are acceptable to use as the _device system unique ID_.
|
|
====
|
|
|
|
. Create the `{user-profile-dir}/[replaceable]_my-profile_/tuned.conf` configuration file. In the file, set the following options:
|
|
|
|
.. Optional: Include an existing profile:
|
|
+
|
|
[subs="quotes"]
|
|
----
|
|
[main]
|
|
include=_existing-profile_
|
|
----
|
|
|
|
.. Set the selected disk scheduler for the device that matches the WWN identifier:
|
|
+
|
|
[subs="quotes"]
|
|
----
|
|
[disk]
|
|
devices_udev_regex=_IDNAME_=_device system unique id_
|
|
elevator=_selected-scheduler_
|
|
----
|
|
+
|
|
Here:
|
|
|
|
* Replace _IDNAME_ with the name of the identifier being used (for example, `ID_WWN`).
|
|
* Replace _device system unique id_ with the value of the chosen identifier (for example, `0x5002538d00000000`).
|
|
+
|
|
To match multiple devices in the `devices_udev_regex` option, enclose the identifiers in parentheses and separate them with vertical bars:
|
|
+
|
|
[subs="quotes"]
|
|
----
|
|
devices_udev_regex=(ID_WWN=_0x5002538d00000000_)|(ID_WWN=_0x1234567800000000_)
|
|
----
|
|
|
|
. Enable your profile:
|
|
+
|
|
[subs="quotes"]
|
|
----
|
|
# tuned-adm profile [replaceable]__my-profile__
|
|
----
|
|
|
|
.Verification steps
|
|
|
|
. Verify that the TuneD profile is active and applied:
|
|
+
|
|
[subs="quotes"]
|
|
----
|
|
$ tuned-adm active
|
|
|
|
Current active profile: [replaceable]_my-profile_
|
|
----
|
|
+
|
|
----
|
|
$ tuned-adm verify
|
|
|
|
Verification succeeded, current system settings match the preset profile.
|
|
See TuneD log file ('/var/log/tuned/tuned.log') for details.
|
|
----
|
|
|
|
|
|
[role="_additional-resources"]
|
|
.Additional resources
|
|
ifndef::pantheonenv[]
|
|
* xref:customizing-tuned-profiles_tuned-documentation[Customizing Tuned profiles]
|
|
endif::[]
|
|
ifdef::pantheonenv[]
|
|
* xref:assemblies/assembly_customizing-tuned-profiles.adoc[Customizing Tuned Profiles]
|
|
endif::[]
|