How to increase the number of Oracle connections

The number of connections to Oracle (sessions) is related to the number of processes (process) in its parameter file, and their relationships are as follows:

Sessions= (1.1*process+5)

But when we increase the number of process numbers, the database does not start. That's because we've also missed a Unix system parameter: It's semmns in/etc/system/, which is the semaphore parameter of the UNIX system. Each process consumes one semaphore. After adjusting the semmns,
The UNIX operating system needs to be restarted for parameters to take effect. However, its size is subject to hardware memory or Oracle SGA. Range
can range from 200--2000.

The Semmns formula is: Semmns>processes+instance_processes+system

Processes= the value of the database parameter processes instance_processes=5 (Smon,pmon,dbwr,lgwr,arch)

The amount of signal consumed by the system= system. The amount of semaphore consumed by the system can be detected by the following command: #ipcs-SB

The column Nsems shows the system has consumed the semaphore.

Some other connection-related parameters, such as Licence_max_sessions, licence_sessions_warning, and so on, are the default settings for
0, which is no limit. We can use the database boldly and confidently.