1. What is semaem?

Maximum adjust-on-exit value. This should almost always be left alone. The default is 16384; the maximum is 32767.

2. What is semvmx?

Maximum value of a semaphore. This should never exceed 32767 (default value) unless SEM_UNDO is never used. The default is 32767; the maximum is 65535.

3. What is semusz?

Number of bytes required for semume undo structures. This should not be tuned; it is set to semume x (1 + sizeof(undo)). The default is 96; the maximum is 2 GB.

4. What is semume?

Maximum number of undo structures per process. This should be set to semopm times the number of processes that will be using semaphores at any one time. The default is 10; the maximum is 2 GB.

5. Explain semopm (max-sem-ops in Solaris 10+)?

Maximum number of semaphore operations that can be performed in each semop call. The default in Solaris 2.5.1-9 is 10, the maximum is 2 GB. Solaris 10 increased the default to 512.

6. Explain semmsl (max-sem-nsems in Solaris 10+)?

Maximum number of semaphores per semaphore set. The default is 25, the maximum is 65535.

7. What is semmnu?

Maximum number of undo structures in the system. This should be set to semmni so that each control structure has an undo structure. The default is 30, the maximum is 2 GB.

8. What is semmns?

Maximum number of semaphores in the system. Each structure uses 16 bytes. This parameter should be set to semmni x semmsl. The default is 60; the maximum is 2GB.

9. Explain semmni (max-sem-ids in Solaris 10+)?

Maximum number of systemwide semaphore sets. Each control structure consumes 84 bytes. For Solaris 2.5.1-9, the default setting is 10; for Solaris 10, the default setting is 128. The maximum is 65535

10. What is semmap?

This sets the number of entries in the semaphore map. This should never be greater than semmni. If the number of semaphores per semaphore set used by the application is "n" then set
semmap = ((semmni + n - 1)/n)+1
or more. Alternatively, we can set semmap to semmni x semmsl. An undersized semmap leads to "WARNING: rmfree map overflow" errors. The default setting is 10; the maximum for Solaris 2.6 is 2GB. The default for Solaris 9 was 25; Solaris 10 increased the default to 512. The limit is SHRT_MAX.

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