10.2.1 Tuning Semaphore Parameters
Refer to the following guidelines if the default semaphore parameter values are too low to accommodate all Oracle processes.
Note:
Oracle recommends that you refer to the operating system documentation for more information about setting semaphore parameters.
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Calculate the minimum total semaphore requirements using the following formula:
2 * sum (process parameters of all database instances on the system) + overhead for background processes + system and other application requirements
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Set
semmns(total semaphores systemwide) to this total. - 
                     
Set
semmsl(semaphores for each set) to 250. - 
                     
Set
semmni(total semaphores sets) tosemmnsdivided bysemmsl, rounded up to the nearest multiple of 1024.