Displaying and Changing Kernel Parameter Values

Use these procedures to display the current value specified for resource controls and to change them if necessary:

Displaying Resource Control Values

1. To display the current values of the resource control:

   $ id -p // to verify the project id
   uid=100(oracle) gid=100(dba) projid=1 (group.dba)
   $ prctl -n project.max-shm-memory -i project group.dba
   $ prctl -n project.max-sem-ids -i project group.dba

2. To change the current values use the prctl command. For example:

   • To modify the value of max-shm-memory to 6 GB:

     # prctl -n project.max-shm-memory -v 6gb -r -i project group.dba

   • To modify the value of max-sem-ids to 256:

     # prctl -n project.max-sem-ids -v 256 -r -i project group.dba

   Note:

   When you use the prctl command (Resource Control) to change system parameters, you do not have to restart the system for these parameter changes to take effect. However, the changed parameters do not persist after a system restart.

Modifying Resource Control Values

Use the following procedure to modify the resource control project settings, so that they persist after a system restart:

1. By default, Oracle instances are run as the oracle user of the dba group. A project with the name group.dba is created to serve as the default project for the oracle user. Run the id command to verify the default project for the oracle user:

   # su - oracle
   $ id -p
   uid=100(oracle) gid=100(dba) projid=100(group.dba)
   $ exit

2. To set the maximum shared memory size to 2 GB, run the projmod command:

   # projmod -sK "project.max-shm-memory=(privileged,2G,deny)" group.dba

   Alternatively, add the resource control value project.max-shm-memory=(privileged,2147483648,deny) to the last field of the project entries for the Oracle project.

3. Check the values for the /etc/project file:

   # cat /etc/project

   The output is similar to the following:

   system:0::::
   user.root:1::::
   noproject:2::::
   default:3::::
   group.staff:10::::
   group.dba:100:Oracle default project ::: project.max-shm-memory=(privileged,2147483648,deny)

4. To verify that the resource control is active, check process ownership, and run the commands id and prctl:

   # su - oracle
   $ id -p
   uid=100(oracle) gid=100(dba) projid=100(group.dba)
   $ prctl -n project.max-shm-memory -i process $$
   process: 5754: -bash
   NAME                    PRIVILEGE     VALUE     FLAG     ACTION    RECIPIENT
   project.max-shm-memory  privileged    2.00GB     -       deny 

Note:

The value for the maximum shared memory depends on the SGA requirements and should be set to a value greater than the SGA size.