GCS_SERVER_PROCESSES

Property Description
Parameter type Integer
Default value If 1 - 3 CPUS, then 1

If 4 - 15 CPUs, then 2

If 16 or more CPUs, then 2 + (CPUs / 32). If the result includes a fraction, then the fraction is disregarded. For example, if you had 20 CPUs, then 2 + (20 / 32) would equal 2 GCS processes.Foot 1 

If CLUSTER_DATABASE is set to false, then 0

If ASM, then 1
Modifiable No
Range of values 1 to 36
Basic No
Oracle RAC Multiple instances can have different values.

Footnote 1 On certain operating systems, the RDBMS optimizes the default allocation of background GCS server processes based on the core to thread ratio of the CPU.

GCS_SERVER_PROCESSES specifies the number of background GCS server processes (LMS0, ... LMS9 and LMSa, ... LMSz) to serve the inter-instance traffic among Oracle RAC instances. GCS server processes are only seen in an Oracle RAC environment.