Lesson 4	cman.ora file
Objective	Describe the Structure and Function of the cman.ora File

Structure and Function of cman.ora File in Oracle 19c

The cman.ora file in Oracle 19c is a configuration file used for Oracle Clusterware's Cluster Manager (CMAN) process, which is responsible for managing and monitoring Oracle Real Application Clusters (RAC). This file plays an important role in configuring the Oracle Clusterware environment and helps define the parameters related to communication and cluster management.
Structure of cman.ora
The cman.ora file is typically located in the

$GRID_HOME/network/admin

directory on each node in the cluster. It is a plain text file and contains several configuration parameters that dictate how the Cluster Manager process behaves. The basic structure of `cman.ora` is composed of one or more sections containing key-value pairs, where each key represents a specific configuration option and the value is the setting for that option.
Key Parameters in `cman.ora`

CMAN_PORT: Defines the port number on which the Cluster Manager process will listen for client connections. This is crucial for inter-node communication within an Oracle RAC environment.
```
    CMAN_PORT=1527
    
```
USE_OCI: Specifies whether to use the Oracle Call Interface (OCI) for communication between nodes in the cluster. Setting this parameter to TRUE can improve performance for certain configurations.
```
    USE_OCI=TRUE
    
```
CLUSTER_INTERFACE: Defines the specific network interface used for inter-node communication within the RAC. This ensures that the CMAN process uses the correct physical or virtual interface.
```
    CLUSTER_INTERFACE=eth0
    
```
LISTENER: This specifies whether or not to use the Oracle Listener to manage connections. The value is typically set to ON or OFF.
```
    LISTENER=ON
    
```
LOG_LEVEL: Controls the verbosity of the logs generated by the Cluster Manager process. This is helpful for troubleshooting and debugging.
```
    LOG_LEVEL=3
    
```
CMAN_ADJUSTMENT_INTERVAL: Specifies the frequency of monitoring and adjustment intervals for the CMAN process. This ensures that the cluster state is checked and adjusted periodically to maintain a stable environment.
```
    CMAN_ADJUSTMENT_INTERVAL=60
    
```
CMAN_LOG: This parameter indicates the location where CMAN logs will be stored. It helps in monitoring and diagnosing issues with the Cluster Manager.
```
    CMAN_LOG=/u01/app/grid/log
    
```

Function of cman.ora The cman.ora file has several critical functions in the Oracle RAC environment:

Cluster Communication: It configures the Cluster Manager to facilitate efficient communication between the nodes in an Oracle RAC setup. This includes specifying the ports and interfaces for inter-node traffic.
Cluster Health Monitoring: The parameters in the cman.ora file allow the Cluster Manager to monitor the health and status of each node in the cluster. It ensures that all nodes remain in sync and that any failure or issue is detected promptly.
Optimizing Performance: By setting parameters such as USE_OCI and CMAN_PORT, it helps to tune performance for better scalability and response times for applications running in a RAC environment.
Diagnostic Logging: The cman.ora file allows for configuration of logging, which is essential for troubleshooting and tracking the performance of the Cluster Manager process. This is crucial for ensuring the availability and stability of Oracle RAC.

Conclusion The cman.ora file in Oracle 19c is a key configuration file for the Oracle Clusterware environment. It governs important settings related to communication, health monitoring, and logging within Oracle Real Application Clusters (RAC). Proper configuration of this file is vital for ensuring efficient cluster management, monitoring, and optimal performance in a high-availability Oracle RAC setup.

The CMAN utility is controlled by the cman.ora file. The cman.ora file contains all of the configuration directives that are used when CMAN is started. The cman.ora file consists of three sections:

CMAN (which defines the listening address for the Connection Manager)
CMAN_PROFILE (which defines general configuration parameters)
CMAN_RULES (which defines rules for filtering incoming connection requests)

The cman.ora file is very similar in function to the listener.ora file. Earlier in this course, you learned to configure the listener.ora to listen on separate addresses. The cman.ora file can also be configured to listen on separate addresses.
The example below illustrates how the Connection Manager configuration file would look if you configured it to listen on two addresses, SPX and TCP/IP. Note that a Connection Manager can listen on any protocol that Oracle supports.

CMAN=  
    (ADDRESS_LIST=  
       (ADDRESS=  
            (PROTOCOL=SPX)  
            (SERVICE=CMAN)  
       )  
       (ADDRESS=  
           (PROTOCOL=TCP)  
           (HOST=CMAN.DILBERT)  
           (PORT=1600)  
       )  
    )

cman.ora Trace Parameters

Table 6-4 describes the trace parameters settings for Oracle Connection Manager that can be set in the cman.ora file.
Table 6-4 cman.ora Trace Parameters

cman.ora Parameter	Description
TRACE_DIRECTORY	The destination directory for trace files. By default, the directory is ORACLE_HOME/network/trace.
TRACE_FILELEN;	The size of the trace file in KB. When the size is reached, the trace information is written to the next file. The number of files is specified with the TRACE_FILENO parameter.
TRACE_FILENO	The number of trace files for tracing. When this parameter is set along with the TRACE_FILELEN parameter, trace files are used in a cyclical fashion. The first file is filled, then the second file, and so on. When the last file has been filled, the first file is reused, and so on. The trace file names are distinguished from one another by their sequence number. For example, if this parameter is set to 3, then the Oracle Connection Manager trace files for the gateway processes would be named instance-name_cmgw1_pid.trc, instance-name_cmgw2_pid.trc and instancename_cmgw3_pid.trc. In addition, trace events in the trace files are preceded by the sequence number of the file.
TRACE_LEVEL	The level of detail the trace facility records for the listener. The trace level value can either be a value within the range of 0 (zero) to 16 where 0 is no tracing and 16 represents the maximum amount of tracing or one of the following values: off (equivalent to 0) provides no tracing. user (equivalent to 4) traces to identify user-induced error conditions. admin (equivalent to 6) traces to identify installation-specific problems. support (equivalent to 16) provides trace information for troubleshooting by Oracle Support Services. The Oracle Connection Manager listener, gateway, and CMADMIN processes create trace files on both Linux and Microsoft Windows.
TRACE_TIMESTAMP	If the TRACING parameter is enabled, then a time stamp in the form of dd-mon-yyyy hh:mi:ss:mil is created for every trace event in the listener trace file.

The next lesson shows you how to use CMAN’s connection concentration feature.