Consultor Eletrônico

Status: Verified

GOAL:

HP-UX 11 Configurable Semaphore Limits Parameters

FACT(s) (Environment):

HP-UX 11 32-bit
HP-UX 11 64-bit

FIX:

WARNING: Changing kernel parameters to improper or inappropriate values or combinations of values can cause data loss, system panics, or other (possibly very obscure and/or difficult to diagnose) operating anomalies, depending on which parameters are set to what values.

Before you alter the value of any configurable kernel parameter, be sure you know the implications of making the change. Many parameters interact, and their values must be selected in a balanced manner.

Settings recommended by Progress are for Progress applications. The values required by Progress must be added to the current kernel parameter values. In other words these recommendations do not take into account the requirement of UNIX operating system and/or any other application that uses shared memory and semaphores.

Configurable kernel parameters are available to limit the number of sets of semaphores that can exist simultaneously on the system and the total number of individual semaphores available to users that can exist simultaneously on the system. A fixed limit on the number of semaphores that can exist in a set (500) is not configurable.

The following eight kernel parameters control System V IPC semaphore operating limits:

- sema

(Series 700 only). Enable or disable IPC semaphores at system boot time.

   Minimum = 0 (exclude System V IPC semaphore code from kernel)
    Maximum = 1 (include System V IPC semaphore code in kernel)
    Default = 1

- semaem

Maximum value by which a semaphore can be changed in a semaphore "undo" operation.

   Minimum = 0
    Maximum = semvmx or 32767, whichever is smaller
    Default = 16384

- semmap

Size of free-semaphores resource map for allocating requested sets of semaphores.

   Minimum = 4
    Maximum = Memory limited
    Default = semmni + 2

- semmni

Maximum number of sets of IPC semaphores allowed on the system at any given time.

   Minimum = 2
    Maximum = Memory limited
    Default = 64

- semmns

Total system-wide number of individual IPC semaphores available to system users.

   Minimum = 2
    Maximum = Memory limited
    Default = 128

- semmnu

Maximum number processes that can have undo operations pending on any given IPC semaphore on the system.

   Minimum = 1
    Maximum = nproc - 4
    Default = 30

- semume

Maximum number of IPC semaphores that a given process can have undo operations pending on.

   Minimum = 1
    Maximum = semmns
    Default = 10

- semvmx

Maximum value any given IPC semaphore is allowed to reach (prevents undetected overflow conditions).

   Minimum = 1
    Maximum = 65535
    Default = 32767