Setting the kernel.shmmax parameter does not reserve or allocate any shared memory. SHMMAX is a safeguard parameter that sets the upper limit of how much shared memory a process can allocate when requested.
This posting has been moved from the Oracle Linux forum space to the R.A.C. forum space for closer topic alignment.
Your inquiry is NOT specific to Oracle Linux.
It is a generic question applicable to most any *NIX operating environment.
It discusses the requirements specific to the application(s) you are installing on the OS you happened to have chosen.