Commands Reference, Volume 5

tundefault Command

Purpose

Reset all tunable parameters to their default value.

Syntax

tundefault [ -r | -p ]

Description

The tundefault command launches all the tuning commands (ioo, vmo, schedo, no and nfso) with the -D flag. This resets all the AIX tunable parameters to their default value, except for parameters of type Bosboot and Reboot, and parameters of type Incremental set at values bigger than their default value, unless -r was specified. Error messages are displayed for any parameter change impossible to make.

Flags

-p	Makes the changes permanent: resets all the tunable parameters to their default values and updates the /etc/tunables/nextboot file.
-r	Defers the reset to their default value to next reboot. This clears stanza(s) in the /etc/tunables/nextboot file, and if necessaty, proposes bosboot and warns that a reboot is needed

Tunable Parameter Types

Dynamic	Can be changed at any time.
Static	Can never be changed
Reboot	Can only be changed during the reboot sequence
Bosboot	Can only be changed by running bosboot and rebooting the machine
Mount	Changes made are only effective for future filesystems or directory mountings
Incremental	Can only be incremented, except at boot time.

Examples

To permanently reset all tunable parameters to their default values, type:
```
tundefault -p
```
All of the tuning commands are launched with the -Dp flags. This resets all the tunable parameters to their default value. This also updates the /etc/tunables/nextboot file. This command completely and permanently resets all tunable parameters to their default values.
To defer the setting of all tunable parameters until next reboot, type:
```
tundefault -r  
```
Calls all tuning commands with -Dr. This clears all of the stanzas in the /etc/tunables/nextboot file, and if necessary, proposes bosboot and displays a message warning that a reboot is necessay to make the changes effective.

Files

/usr/sbin/tundefault	Contains the tundefault command.
/etc/tunables/	Contains all the tunable files.

Related Information

The schedo Command, vmo command, ioo command, no command, nfso command, tuncheck Command, tunrestore Command, and tunsave Command.

Tunables File Format in AIX 5L Version 5.2 Files Reference.

Kernel Tuning in AIX 5L Version 5.2 Performance Tools Guide and Reference.