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Tunable

6 minute read.

Last Modified 2024-03-15 13:07 EDT

The SCALE CLI guide is a work in progress! New namespace and command documentation is continually added and maintained, so check back here often to see what is new!

Tunable Namespace

The tunable namespace has six commands, and is based on tuned settings functions found in the SCALE API and web UI. It provides access to tunable configuration methods through the tunable namespace commands.

Tunable Commands

The following tunable namespace commands allow you to create and manage tuned settings. Tunables configure kernel parameters while the system is running. Configured settings generally take effect immediately.

You can enter commands from the main CLI prompt or from the system namespace prompt.

Create Command

The create command allows you to configure a new tunable.

Using the Create Command

Description

create has three required and three optional properties (see table below). Enter the command string with all required and any optional properties you want and then press Enter. create returns the percent complete status of the tunable create job.

Create Properties

Property	Required	Description	Syntax Example
`type`	Yes	Enter the type of tunable to configure. Options are `SYSCTL`, `UDEV`, or `ZFS`.	`type=SYSCTL`
`var`	Yes	Enter the name of the variable to configure. If `type` is: `SYSCTL` then `var` is a sysctl name (e.g. kernel.watchdog). `UDEV` then `var` is an udev rules file name (e.g. 10-disable-usb). Automatically adds the .rules suffix to the file name. `ZFS` then `var` is a ZFS kernel module parameter name (e.g. zfs_dirty_data_max_max).	`var=kernel.watchdog`
`value`	Yes	Enter the value of the variable. If `type` is: `SYSCTL` then `value` is the corresponding value (e.g. 0) for the sysctl name in `var`. `UDEV` then `value` is the contents (e.g. BUS==“usb”, OPTIONS+=“ignore_device”) of the udev rules file in `var`. `ZFS` then `value` is the corresponding value for the ZFS kernel module parameter in `var`.	`value=0`
`comment`	No	Enter a human-readable description for the tunable.	`comment=TunableDescription`
`enabled`	No	If `enabled` is `false`, creates and saves the tunable without activating it. Update to `false` to disable a tunable without deleting it. Defaults to `true`.	`enabled=true`
`update_initramfs`	No	If `update_initramfs` is `false`, initramfs is not updated after creating a ZFS tunable. If needed, use `update` on an existing tunable to reconfigure `update_initramfs` to `true`.	`update_initramfs=true`

Usage

From the CLI prompt, enter:

system tunable create type=SYSCTL var="kernel.watchdog" value="0"

Where

SYSCTL is the type of tunable
kernel.watchdog is the name of the variable to configure
0 is the value of the named variable.

Command Example

system tunable create type=SYSCTL var="kernel.watchdog" value="0" comment="Watchdog" enabled=true update_initramfs=true
[0%] ...
[100%] ...

Delete Command

The delete command removes a configured tunable from the system.

Using the Delete Command

Description

delete has one required property, id. Use query to find the id number of the tunable to remove. Enter the command then press Enter. delete returns the percent complete status of the delete task.

Usage

From the CLI prompt, enter:

system tunable delete id=1

Where 1 is the id number of the tunable to delete.

Command Example

system tunable delete id=1
[0%] ...
[100%] ...

Get_instance Command

The get_instance command allows you to inspect the configuration of an existing tunable.

Using the Get_instance Command

Description

get_instance has one required property, id. Use query to find the id number of the tunable to inspect. Enter the command then press Enter. get_instance returns a table containing configured settings for the tunable matching id.

Usage

From the CLI prompt, enter:

system tunable get_instance id=1

Where 1 is the id of the tunable to query.

Command Example

system tunable get_instance id=1
+------------+-----------------+
|         id | 1               |
|       type | SYSCTL          |
|        var | kernel.watchdog |
|      value | 0               |
| orig_value | 1               |
|    comment | Watchdog        |
|    enabled | true            |
+------------+-----------------+

Query Command

The query command allows you to inspect all tuned settings on the system.

Using the Query Command

Description

query does not require entering properties or arguments. Enter the command and then press Enter. query returns a table containing all configured tunable settings.

Usage

From the CLI prompt, enter:

system tunable query

Command Example

system tunable query
+----+--------+------------------------+-----------+------------+----------+---------+
| id | type   | var                    | value     | orig_value | comment  | enabled |
+----+--------+------------------------+-----------+------------+----------+---------+
| 2  | ZFS    | zfs_dirty_data_max_max | 783091712 | 2076269568 |          | true    |
| 3  | SYSCTL | kernel.watchdog        | 0         | 1          | Watchdog | true    |
+----+--------+------------------------+-----------+------------+----------+---------+

Tunable_type_choices Command

The tunable_type_choices command allows you to view the available tunable types.

Using the Tunable_type_choices Command

Description

tunable_type_choices does not require entering properties or arguments. Enter the command and then press Enter. tunable_type_choices returns a table containing the available choices.

Usage

From the CLI prompt, enter:

system tunable tunable_type_choices

Command Example

system tunable tunable_type_choices
+--------+--------+
| SYSCTL | SYSCTL |
|   UDEV | UDEV   |
|    ZFS | ZFS    |
+--------+--------+

Update Command

The update command allows you to reconfigure an existing tuned setting.

Using the Update Command

Description

update has one required property, id, and four optional properties (see table below). Use query to find the id number of the tunable to update. Enter the command string with the required property and any optional properties to change. Separate multiple property and value pairs with a space. Then press Enter. update returns the percent complete status of the update task.

Update Properties

Property	Required	Description	Syntax Example
`id`	Yes	Enter the id number of an existing tuned setting. Use `query` to find the id number of the tunable to update.	`id=1`
`value`	No	Enter the new value for the existing `type` and variable (`var`) matching `id`. If `type` is: `SYSCTL` then `value` is the corresponding value (e.g. 0) for the sysctl name in `var`. `UDEV` then `value` is the contents (e.g. BUS==“usb”, OPTIONS+=“ignore_device”) of the udev rules file in `var`. `ZFS` then `value` is the corresponding value for the ZFS kernel module parameter in `var`.	`value=0`
`comment`	No	Enter a human-readable description for the tunable.	`comment=TunableDescription`
`enabled`	No	Update `enabled` to `false` to disable a tunable without deleting it.	`enabled=true`
`update_initramfs`	No	Set to `false` to update the tuned setting but not update initramfs. To to update initramfs for an existing tunable (if `false` at creation), reconfigure `update_initramfs` to `true`.	`update_initramfs=true`

Usage

From the CLI prompt, enter:

system tunable update id=1 PROPERTY=VALUE

Where:

1 is the id of an existing tuned setting
PROPERTY is an optional property to update
VALUE is the new setting for that property.

Command Example

system tunable update id=3 value=1 comment=KernelWatchdog
[0%] ...
[100%] ...

Tunable

Tunable Namespace

Tunable Commands

Create Command

Description

Usage

Delete Command

Description

Usage

Get_instance Command

Description

Usage

Query Command

Description

Usage

Tunable_type_choices Command

Description

Usage

Update Command

Description

Usage

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