How to Modify Linux Kernel Semaphores Parameters
Posted by Planet Malaysia on March 2, 2009
Oracle, DB2 or SAP uses UNIX/Linux resources such as shared memory, swap space, and semaphores extensively for interprocess communication. If the kernel parameters settings are insufficient, you will experience some problems during installation and/or instance startup.
Basically this post will focus on “How to modify Linux Kernel Semaphores parameters”.
Semaphores can best be described as counters which are used to provide synchronization between processes or between threads within a process for shared resources like shared memories. System V semaphores support semaphore sets where each one is a counting semaphore. So when an application requests semaphores, the kernel releases them in “sets”. The number of semaphores per set can be defined through the kernel parameter SEMMSL.
1)Show current SEMAPHORES parameter
server01:~ # ipcs -l
—— Semaphore Limits ——–
max number of arrays = 1024
max semaphores per array = 1250
max semaphores system wide = 256000
max ops per semop call = 100
semaphore max value = 32767
OR
server01:~ # cat /proc/sys/kernel/sem
1250 256000 100 1024
OR
server01:~ # cat /etc/sysctl.conf
kernel.sem = 1250 256000 100 1024
2)How to modify Linux kernel semaphores parameters
server01:~ # vi /etc/sysctl.conf
#search for and change the setting by request
kernel.sem = 4096 512000 1600 9000
Save it and run
server01:~ # sysctl -p /etc/sysctl.conf
3)Show SEMAPHONES parameters
server01:~ # cat /etc/sysctl.conf |grep sem
kernel.sem = 4096 512000 1600 9000
OR
server01:~ # ipcs -l
kernel.sem = 4096 512000 1600 9000
—— Semaphore Limits ——–
max number of arrays = 9000
max semaphores per array = 4096
max semaphores system wide = 512000
max ops per semop call = 1600
semaphore max value = 32767
OR
server01:~ # cat /proc/sys/kernel/sem
4096 512000 1600 9000
Hope this can help!
Possibly Related Posts:
- How to add Dell PERC Drivers into VMware Converter Cold Clone ISO
- Top 10 Free Anti Virus
- How to Install Webmin on OpenFiler
- Microsoft SQL 2008 Agent not starts
- VMware Workstation 7 Serial Key
Comments
Leave a Reply