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|
System Setting
Required to Run Oracle Software
Oracle Database Tips by Donald Burleson |
Located in the Code Depot for this book (see
Appendix B) is a script called
os_prep.sh. This script should be run as the root user on each
node. It will automatically write each of the settings described in
the following section to the necessary system configuration files.
|
SYSTEM SETTING |
DESCRIPTION |
|
kernel.shmni (leave at default) |
The maximum number of system-wide shared
memory segments. |
|
kernel.shmmax =2147483648 |
The maximum size of each shared memory
segment. It should be set to a minimum of half the real memory.
Setting it at 2 gigabytes will not cause trouble even if there is
minimal RAM installed. It is saved in file /etc/sysctl.conf. |
|
kernel.shmall (leave at default) |
Defines the maximum amount of shared
memory that may be in use at any time on the system. |
|
kernel.shmseg (leave at default) |
Defines the maximum number of shared
memory segments to which a single process can attach. |
|
Semmsl |
Maximum number of semaphores per set. |
|
Semmns |
Total number of semaphores in the system. |
|
Semopm |
Maximum number of operations per semop
call. |
|
Semmni |
Maximum number of semaphore sets. |
|
The previous four semaphore parameters are
saved in /etc/sysctl.conf using the following syntax, delimited
by white space:
### kernel.sem=semmsl semmns semopm semmni
kernel.sem=250 32000 100 128 |
|
fs.file-max = 65536 |
Determines the maximum number of files
that any single process can open. It is saved in file /etc/sysctl.conf. |
|
net.core.rmem_default=262144 |
Each network socket is allocated a send
buffer for outbound packets and a receive socket for inbound
packets. To support high data rates required for Oracle's cache
fusion, these four parameters are increased. It is saved in file
/etc/sysctl.conf. |
|
net.core.wmem_default=262144 |
|
net.core.rmem_max=262144 |
|
net.core.wmem_max=262144 |
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ulimit ?u 16384 |
Sets the maximum number of processes that
a user can start. The Oracle user starts the database, which
requires a high limit. It is saved in file /etc/rc.local. |
Table 4.2:
System settings and descriptions
A few system settings are specific to a RAC on a
Firewire configuration. The following table lists those settings.
These settings are also included in the
os_prep.sh script.
|
System Setting |
Description |
|
options sbp2 sbp2_exclusive_login=0
post-install sbp2 insmod sd_mod
post-remove sbp2 rmmod sd_mod |
Settings specific to the kernel modified
for dual logging on the firewire drive. It is saved in the file
/etc/modules.conf. |
Table 4.3:
RAC specific settings on Firewire
confiruration
Running the os_prep.sh
Script
Run the
os_prep.shscript as shown in Figure 4.5. When the script has
finished, use the init 6 command to reboot the node. Afterward,
proceed to the next node and follow the same steps to install the
modified kernel. Run the
os_prep.sh script and reboot.
Verifying the
External Drive
With the modified kernel installed, the
os_prep.shrun, and each node rebooted, the external drive
should now be available to each node. The commands shown in Figure 4.6
are used to verify that a given node has detected the external drive.
If the external drive has been partitioned, the fdisk ?l | grep sd
command will return one line for the disk and one line for each
partition. If the external drive is not detected, which is common for
a first boot to the new kernel, another reboot of the node in question
will usually fix the problem.
 |
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Oracle Real Application Clusters" by Edward Stoever.
You can buy it direct from the publisher for 30%-off and get
instant access to the code depot of Oracle tuning scripts. |
|
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