Hi,
you need to chech the /etc/system file.
This file contains directives for the operating system on how much memory to preserve for the Oracle server, how much semaphores for the oracle processes:

Shared Memory:
shmmax = The maximum size(in bytes) of a single shared memory segment.
shmmin = The minimum size(in bytes) of a single shared memory segment.
shmmni = The number of shared memory identifiers.
shmseg = The maximum number of shared memory segments that can be attached by a process.

Semaphores:
semmns = The number of semaphores in the system.
semmni = The number of semaphore set identifiers in the system; determines the number of semaphore sets that can be created at any one time.
semmsl = The maximum number of sempahores that can be in one semaphore set. It should be same size as maximum number of Oracle processes (The PROCESSES parameter in the init.ora file).

The Formula
SEMMNS = [(largest PROCESSES parameter) *2 + (other instance processes)] + [(# of instances) * 10]
SEMMSL = 10 + largest PROCESSES parameter.