OS-specific considerations for setting shared memory and semaphore parameters

For information about operating system-specific considerations for setting shared memory and semaphore parameters, refer to the following sections:

Setting shared memory and semaphore parameters on Linux systems

The shared memory and semaphore requirements on Linux are the same as the requirements for other UNIX variants. 

If there are no other shared memory intensive applications running on the Linux computer (such as Oracle) it is not typically necessary to change the default IPC kernel settings under Linux. The current shared memory settings on the computer can be seen by running the ipcs -l  command.

The default value for each of these parameters is well above the requirements for BMC TrueSight Capacity Optimization. If other applications were running on the system that used shared memory and semaphores, it would be necessary to ensure that the settings had been adjusted to the recommendations for those applications (if they were higher than the default values). 

Shared memory and semaphore settings can be changed in the Linux kernel by editing the kernel settings files in /proc/sys/kernel. The files are: sem, shmall, shmmax, shmmni. The shm* files contain a single value equal to the setting on the computer. The sem file has four values separated by tabs. Updating these files changes the specified setting in the running kernel. 

Therefore, there is no reason to change the Linux kernel default shared memory and semaphore settings for BMC TrueSight Capacity Optimization. The default kernel limits are sufficient to run BMC TrueSight Capacity Optimization on the computer. Even when running another application that used shared memory and semaphores (such as Oracle) it would probably still be unnecessary to increase the limits further to make room for BMC TrueSight Capacity Optimization (although it would probably be necessary to change them for a large Oracle instance itself to run).

Setting shared memory and semaphore parameters on HP systems

On HP-UX you can use the SAM tool to change the settings for resource limits and to reconfigure the kernel. SAM relinks the kernel. See the man pages for more information about using SAM for this purpose.

The different IPC Shared Memory and Semaphore parameters available on HP-UX are the same as the parameters available on Solaris. Unlike Solaris, the default IPC Shared Memory and Semaphore settings on HP-UX are high enough that the product might work properly without any increase in the settings, as long as there are no other shared memory consuming applications. However, as a general rule, BMC recommends that the settings be increased to ensure that there are IPC resources available for the BMC TrueSight Capacity Optimization product.

Setting shared memory and semaphore parameters on AIX systems

There are no IPC Shared Memory or Semaphore limits on AIX because the kernel dynamically allocates shared memory and semaphore resources on AIX. Therefore, the only way to run out of these resources is to use up all available memory on the computer. 

You can list allocated shared memory and semaphore resources using ipcs -a. However, there is no equivalent to Solaris's sysdef command on AIX because there are no allocation limits. Insufficient shared memory or semaphores is not an issue on AIX.

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