GCS_SERVER_PROCESSES - LMS process - RAC

 

GCS_SERVER_PROCESSES

GCS_SERVER_PROCESSES specifies the number of background GCS server processes (LMSn and LMnn) to serve the inter-instance traffic among Oracle RAC instances.

If there is high Cache Fusion congestion on the system, the number of GCS server processes could be increased to reduce Cluster wait time. Additionally, the number of GCS server processes could be increased to reduce the application brownout time associated with Cluster reconfiguration and Dynamic Re-mastering (DRM).

Property	Description
Parameter type	Integer
Default value	Oracle calculates the default value as follows (in order of precedence): If CLUSTER_DATABASE is set to false, then 0 If Oracle ASM, then 1 If 1 - 3 CPUS, then 1 If 4 - 15 CPUs, then 2 If 128 or more CPUs and SGA is 100 GB or more, then (CPUs / 6). If the result includes a fraction, then the fraction is disregarded. Otherwise, the value is 2 + (CPUs / 32). If the result includes a fraction, then the fraction is disregarded. For example, if you have 20 CPUs, then 2 + (20 / 32) would equal 2 GCS processes. On NUMA-enabled systems with 32 or more CPUs, the value is rounded up to a multiple of the number of NUMA processor groups, with a limit of (CPUs / 4) rounded down to a multiple of the number of NUMA processor groups.
Modifiable	No
Modifiable in a PDB	No
Range of values	0 if Oracle RAC is disabled (CLUSTER_DATABASE is set to false) 1 to 100 if Oracle RAC is enabled (CLUSTER_DATABASE is set to true)
Basic	No
Oracle RAC	Multiple instances can have different values.

GCS server processes are only seen in an Oracle RAC environment.