Use of no and ODM commands in AIX Servers


no command in AIX is used to tune the network parameters and ODM is a database of system and device configuration information integrated into the OS.

no command

Use the no command to configure network tuning parameters. The no command sets or displays current or next boot values for network tuning parameters. This command can also make permanent changes or defer changes until the next reboot. Whether the command sets or displays a parameter is determined by the accompanying flag.When the no command is used to modify a network option it logs a message to the syslog using the LOG_KERN facility.

Be careful when you use this command. If used incorrectly, the no command can cause your system to become inoperable. Before modifying any tunable parameter, you should first carefully read about all its characteristics in the Tunable Parameters section below, and follow any Refer To pointer, in order to fully understand its purpose. You must then make sure that the Diagnosis and Tuning sections for this parameter truly apply to your situation and that changing the value of this parameter could help improve the performance of your system.


no is used in the following examples. vmo, no, nfso, ioo, raso, and schedo all use similar syntax. lvmo uses different syntax. Below are some of the examples of no command.
  • Reset all networking tunables to the default values 
               no -D (Changed values will be listed)
  • List all networking tunables
                no -a
  • Set a tunable temporarily (until reboot)
               no -o use isno=1
  • Set a tunable at next reboot
                 no -r -o use isno=1
  • Set current value of tunable as well as reboot
                   no -p -o use isno=1
  • List all settings, defaults, min, max, and next boot values
                   no -L
  • Get information on the minperm% vmo tunable
                  vmo -h minperm%
  • Change the maximum number of user processes to 2048
                  chdev -l sys0 -a maxuproc=2048
  • Directory containing tunables settings
                  /etc/tunables/

ODM (OBJECT DATA MANAGER)

It is a database of system and device configuration information integrated into the OS. It is intended for storing system informations software infos(like smit menus and commands, installed filesets) and device infos (like device configurations, tcp/ip config). For safety reasons the ODM data is stored in binary format. All ODM commands use the ODMDIR environment variable, that is set in file /etc/environment. The default value of ODMDIR is /etc/objrepos.

You can create, add, change, retrieve, display, delete, and remove objects and object classes with ODM. You enter ODM commands on the command line. You can put ODM subroutines in a C language program to handle objects and object classes. An ODM subroutine returns a value of -1 if the subroutine is unsuccessful. The specific error diagnostic is returned as the odmerrno external variable (defined in the odmi.h include file). ODM error-diagnostic constants are also included in the odmi.h include file.

Also Read: Frequently Asked Interview Questions and Answers

odmadd
Adds objects to an object class. The odmadd command takes an ASCII stanza file as input and populates object classes with objects found in the stanza file.

odmchange
Changes specific objects in a specified object class.

odmcreate
Creates empty object classes. The odmcreate command takes an ASCII file describing object classes as input and produces C language .h and .c files to be used by the application accessing objects in those object classes.

odmdelete
Removes objects from an object class.

odmdrop
Removes an entire object class.

odmshow
Displays the description of an object class. The odmshow command takes an object class name as input and puts the object class information into odmcreate command format.

odmget
Retrieves objects from object classes and puts the object information into odmadd command format.

Examples of ODM command

  • Query CuDv for a specific item
               odmget -q name=hdisk0 CuDv
  • Query CuDv using the “like” syntax
                odmget -q "name like hdisk?" CuDv
  • Query CuDv using a complex query
               odmget -q "name like hdisk?  and parent like vscsi?" CuDv




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