IMPORTANT Oracle RAC Background Processes

 Oracle RAC Background Processes

The GCS and GES processes, and the GRD collaborate to enable Cache Fusion. The
Oracle RAC processes and their identifiers are as follows:

1. ACMS: Atomic Controlfile to Memory Service (ACMS)
In an Oracle RAC environment, the ACMSper-instance process is an agent that
contributes to ensuring a distributed SGA memory update is either globally
committed on success or globallyaborted if a failure occurs.

2.GTX0-j: Global Transaction Process
The GTX0-jprocess provides transparent supportfor XA global transactions in an
Oracle RAC environment. The database autotunes the number of these processes
based on the workload of XA global transactions.

3. LMON: Global Enqueue Service Monitor
The LMONprocess monitors global enqueues and resources across the cluster and
performs global enqueue recovery operations.

4. LMD: Global Enqueue Service Daemon
The LMDprocess manages incoming remote resource requests within each
instance.

5. LMS: Global Cache Service Process
Note: The SGA size requirements for Oracle RAC are greater than
the SGA requirements for noncluster Oracle databases due to Cache
Fusion.
Overview of Automatic Workload Management
Introduction to Oracle RAC 1-7
The LMSprocess maintains records of the data file statuses and each cached block
by recording information in a Global Resource Directory (GRD). The LMSprocess
also controls the flow of messages to remote instances and manages global data
block access and transmits block images between the buffer caches of different
instances. This processing is part of the Cache Fusion feature.

6. LCK0: Instance Enqueue Process
The LCK0process manages non-Cache Fusion resource requests such as library
and row cache requests.

7. RMSn: Oracle RAC Management Processes (RMSn)
The RMSnprocesses perform manageability tasks for Oracle RAC. Tasks
accomplished by an RMSnprocess include creation of resources related to Oracle
RAC when new instances are added to the clusters.

8 RSMN: Remote Slave Monitor manages background slave process creation and
communication on remote instances. These background slave processes perform
tasks on behalf of a coordinating process running in another instance.