This section explains the tasks that need to be performed before installation.
The system parameters must be tuned.
Tuning values for system parameters
Refer to the following tables for information on the system parameters that require tuning and their values.
Semaphores
For the semaphore settings, specify each parameter value using the following format:
kernel.sem = para1 para2 para3 para4
Parameter | Description | Value | Type |
|---|---|---|---|
para1 | Maximum number of semaphores per semaphore identifier | 1 | Maximum |
para2 | Number of semaphores for the entire system | 2 | Addition |
para3 | Maximum number of operators per semaphore call | 1 | Maximum |
para4 | Number of semaphore operators for the entire system | 2 | Addition |
Message queues
Parameter | Description | Value | Type |
|---|---|---|---|
kernel.msgmnb | Maximum number of messages that can be held in a single message queue | 106496 | Maximum |
kernel.msgmni | Maximum number of message queue IDs | 1024 | Addition |
Settings dependent on the parameter type
Set the parameters as below, depending on the "Type" above.
If the Type is "Maximum":
If the value that has already been set (either the initial value or the previous setting) is equal to or greater than the value in the table above, there is no need to change the parameter value. If the current value is smaller than the value in the table, change the parameter to the value in the table.
If the Type is "Addition":
Add the value in the table to the value that has already been set (either the initial value or the previous setting). Check the upper limit for the system before setting the parameter to the result of the addition, and if the result of the addition is greater than the upper limit for the system, then set the parameter to the upper limit for the system.
Refer to the Linux manuals and other documents for details.
Tuning procedure
Use the following procedure to perform tuning tasks:
Use the following command to check the current settings for the system parameters:
# /sbin/sysctl -a
Example
# /sbin/sysctl -a . . . (omitted) . . . kernel.sem = 250 32000 32 128 . . . kernel.msgmnb = 65536 kernel.msgmni = 16 . . . (omitted) . . .
Refer to "Tuning values for system parameters", and compare the current settings to the values in the tables above. Calculate an appropriate value for each parameter, taking into account the parameter type ("Maximum" or "Addition").
Edit the /etc/sysctl.conf file. Edit the file as shown in the following example:
Example
kernel.sem = 250 32002 32 130 kernel.msgmnb = 106496 kernel.msgmni = 1040
Use the following command to check that the changes have been applied to the /etc/sysctl.conf file:
# /bin/cat /etc/sysctl.conf
To enable the settings in Step 4 above, perform either of the following methods:
Apply the settings by rebooting the system.
# /sbin/shutdown -r now
Apply the settings by executing the "/sbin/sysctl -p" command.
# /sbin/sysctl -p /etc/sysctl.conf (*1)
*1: There is no need to reboot the system if this command is used.
The output of the following command can be used to check that the changes made to the system parameter settings have been applied:
# /sbin/sysctl -a
Example
# /sbin/sysctl -a . . . (omitted) kernel.sem = 250 32002 32 130 . . . kernel.msgmnb = 106496 kernel.msgmni = 1040 . . . (omitted) . . .
