Différences
Ci-dessous, les différences entre deux révisions de la page.
| Prochaine révision | Révision précédente | ||
| informatique:nix:linux:tuning [2012/05/21 14:38] – modification externe 127.0.0.1 | informatique:nix:linux:tuning [2018/02/09 15:44] (Version actuelle) – [Calcul des valeurs] ben | ||
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| Ligne 343: | Ligne 343: | ||
| semaphore max value = 32767 | semaphore max value = 32767 | ||
| </ | </ | ||
| + | |||
| + | ==== Description ==== | ||
| + | |||
| + | ^ Semaphore | ||
| + | |SEMMSL|maximum number of semaphores per array|128| | ||
| + | |SEMMNS|maximum semaphores system-wide| | ||
| + | |SEMOPM|maximum operations per semop call| | ||
| + | |SEMMNI|maximum arrays| | ||
| + | |||
| + | ==== Calcul des valeurs ==== | ||
| + | Source ((https:// | ||
| + | |||
| + | * Calculate the minimum total semaphore requirements using the following formula: | ||
| + | |||
| + | < | ||
| + | sum (process parameters of all database instances on the system) + system and other application requirements | ||
| + | </ | ||
| + | |||
| + | Set semmns (total semaphores systemwide) to this total.\\ | ||
| + | Set semmsl (semaphores per set) to 256.\\ | ||
| + | Set semmni (total semaphores sets) to semmns / semmsl rounded up to the nearest multiple of 1024.\\ | ||
| + | \\ | ||
| + | The following formula can be used as a guide, although in practice, SEMMNS and SEMMNU can be much less than SEMMNI * SEMMSL because not every program in the system needs semaphores. | ||
| + | |||
| + | SEMMNS = SEMMNU = (SEMMNI * SEMMSL) | ||