La commande 'tundefault' permet de replacer les valeurs par défaut des variables systèmes(ioo, vmo, schedo, no, nfso, and raso) sauf celles de type 'bosboot' ou 'reboot'.
L'option '-p' fait des changements permanents dans le fichier /etc/tunables/nextboot et dans le système actuel.
L'option '-r' diffère la remise aux valeurs par défaut au prochain reboot, en effaçant le fichier /etc/tunable/nextboot, propose un 'bosboot' pour refaire l'image système et précise qu'un reboot est nécessaire.
Ci-dessous la documentation officielle.
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, nfso, and raso) 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
Item
Description
-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
necessary, proposes bosboot and warns that a reboot is needed
Tunable Parameter Types
Item
Description
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.
Connect
Changes are only effective for future socket connections.
Examples
1 To permanently reset all tunable parameters to their default values, enter:
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.
2 To defer the setting of all tunable parameters until next reboot, enter:
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 necessary to make the changes effective.
Files
Item
Description
/usr/sbin/tundefault
Contains the tundefault command.
/etc/tunables/
Contains all the tunable files.
