CM Agent Parameters

log_dir

Parameter description: Specifies the directory where CM Agent logs are stored. The value can be an absolute path, or a path relative to the CM Agent data directory.

Parameter type: string.

Unit: none

Value range: valid path of a directory.

Default value: "$GAUSSLOG/cm/cm_agent", indicating that the CM Agent logs are generated in the CM directory in $GAUSSLOG.

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 in Table 2. The modification takes effect only after the CM Agent is restarted.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

log_file_size

Parameter description: Specifies the size of a log file. If a log file exceeds the specified size, a new one is created to record logs.

Parameter type: integer.

Unit: MB

Value range: 0 to 2047

Default value: 16

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2. For example, if this parameter is set to 16 without a unit, it indicates 16 MB. If this parameter is set to 16MB, it indicates 16 MB. The unit must be MB if required.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

log_min_messages

Parameter description: Specifies which message levels are written to the CM Agent log. Each level covers all the levels following it. A lower level indicates that fewer messages will be written into the run log on the server.

Value type: enumerated type.

Unit: none

Value range: debug5, debug1, log, warning, error, and fatal.

Default value: warning

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Set this parameter based on the hard disk size.

Risks and impacts of improper settings: If the level is set to a low value, debugging information may be lost.

incremental_build

Parameter description: Specifies whether a standby DN is incrementally built.

Parameter type: Boolean.

Unit: none

Value range:

• on: Standby DNs are incrementally rebuilt.
• off: Standby DNs are fully rebuilt.

Default value: on

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

alarm_component

Parameter description: Specifies the location of the alarm component that processes alarms.

Parameter type: string.

Unit: none

Value range: valid file path.

• If --alarm-type in the gs_preinstall script is set to 5, no third-party component is connected and alarms are written into system_alarm logs. In this case, the value of alarm_component is /opt/huawei/snas/bin/snas_cm_cmd.
• If --alarm-type in the gs_preinstall script is set to 1, a third-party component is connected. In this case, the value of alarm_component is the absolute path of the executable program of the third-party component.

Default value: "/opt/huawei/snas/bin/snas_cm_cmd"

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

alarm_report_interval

Parameter description: Specifies the interval at which an alarm is reported.

Parameter type: integer.

Unit: second

Value range: 1 to 2147483647

Default value: 1

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large, alarms may not be reported in a timely manner. If the value is too small, the CPU load may increase.

alarm_report_max_count

Parameter description: Specifies the maximum number of times an alarm is reported.

Parameter type: integer.

Unit: none

Value range: 1 to 2592000

Default value: 1

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large, the CPU load may increase.

agent_report_interval

Parameter description: Specifies the interval at which CM Agent reports the instance status.

Parameter type: integer.

Unit: second

Value range: 1 to 2147483647

Default value: 1

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large, CM fault detection and recovery cannot be performed in a timely manner.

agent_phony_dead_check_interval

Parameter description: Specifies the interval at which CM Agent checks whether the DN process is suspended.

Parameter type: integer.

Unit: second

Value range: 0 to 2147483647

Default value: 10

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large, CM fault detection and recovery cannot be performed in a timely manner. If the value is too small, the CPU load increases.

agent_check_interval

Parameter description: Specifies the interval at which CM Agent queries the status of instances, such as the DNs.

Parameter type: integer.

Unit: second

Value range: 1 to 2147483647

Default value: 2

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large, CM fault detection and recovery cannot be performed in a timely manner. If the value is too small, the CPU load increases.

agent_heartbeat_timeout

Parameter description: Specifies the timeout interval for CM Agent to detect the CM Server heartbeat. If CM Agent does not receive the heartbeat message from CM Server within the timeout interval, the CM Agent terminates the connection with CM Server.

Parameter type: integer.

Unit: second

Value range: 2 to 2147483647

Default value: 5

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large or too small, false negative and false positive may occur during fault detection.

agent_connect_timeout

Parameter description: Specifies the time to wait before the attempt of CM Agent to connect to CM Server times out.

Parameter type: integer.

Unit: second

Value range: 0 to 2147483647

Default value: 1

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large or too small, false negative and false positive may occur during fault detection.

agent_connect_retries

Parameter description: Specifies the number of times CM Agent retries to connect to the CM Server.

Parameter type: integer.

Unit: none

Value range: 0 to 2147483647

Default value: 15

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large or too small, false negative and false positive may occur during fault detection.

agent_kill_instance_timeout

Parameter description: Specifies the interval from the time when CM Agent fails to connect to the primary CM Server to the time when CM Agent terminates all instances on the node.

Parameter type: integer.

Unit: second

Value range: 0 to 2147483647

Default value: 0, indicating that the operation of stopping all instances on the node is not initiated.

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: If you want to set this parameter to a value other than 0, ensure that the value is greater than the time required for promoting CM Server to the primary node.

Risks and impacts of improper settings: If the value is too large, CM faults may not be rectified in a timely manner.

security_mode

Parameter description: Specifies whether DNs are started in secure mode.

Parameter type: Boolean.

Unit: none

Value range:

• on: The DN is started in secure mode.
• off: The DN is started in non-secure mode.

Default value: off

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

upgrade_from

Parameter description: Specifies the internal version number of the database before an in-place upgrade. Do not modify the value of this parameter.

Parameter type: integer.

Unit: none

Value range: 0 to 4294967295

Default value: 0

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Manual modification may cause in-place upgrade failures.

process_cpu_affinity

Parameter description: Specifies whether to bind a primary DN process to a CPU core before starting the process. Only Arm is supported.

Parameter type: integer.

Unit: none

Value range: 0 to 2

• If the value is 0, core binding is not optimized.
• If the value is greater than 0, core binding is optimized and the number of physical CPU slices is 2ⁿ.

Default value: 0

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 in Table 2. The modification takes effect only after the database and CM Agent is restarted.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

log_threshold_check_interval

Parameter description: Specifies the interval for compressing and clearing logs.

Parameter type: integer.

Unit: second

Value range: 0 to 2147483647

Default value: 1800

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value. You can adjust the value based on the disk space and scenario requirements.

Risks and impacts of improper settings: If this parameter is set to a large value, too much disk space may be occupied.

log_max_size

Parameter description: Specifies the maximum size of a log file.

Parameter type: integer.

Unit: MB

Value range: 0 to 2147483647

Default value: 10240

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value. You can adjust the value based on the disk space and scenario requirements.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

log_max_count

Parameter description: Specifies the maximum number of logs that can be stored on hard disks.

Parameter type: integer.

Unit: none

Value range: 0 to 10000

Default value: 10000

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value. You can adjust the value based on the disk space and scenario requirements.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

log_saved_days

Parameter description: Specifies the number of days for storing logs.

Parameter type: integer.

Unit: day

Value range: 0 to 1000

Default value: 90

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value. You can adjust the value based on the disk space and scenario requirements.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

enable_log_compress

Parameter description: Specifies whether to enable the log compression function.

Parameter type: Boolean.

Unit: none

Value range:

• on: The log compression function is enabled.
• off: The log compression function is disabled.

Default value: on

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

agent_backup_open

Parameter description: Specifies the standby database instance for DR settings. After this parameter is enabled, CM runs in standby database instance for DR mode.

Parameter type: integer.

Unit: none

Value range: 0 to 3

• 0: No DR relationship is established.
• 1: The Dorado DR relationship is established.
• 2: The streaming replication-based DR relationship is established.
• 3: The logical DR relationship is established.

Default value: 0

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 in Table 2. The modification takes effect only after the CM Agent is restarted.

Setting suggestion: This parameter is internally called. You are advised not to modify it.

Risks and impacts of improper settings: Changing the value of this parameter may cause unexpected results in the database. Retain the default value.

enable_xc_maintenance_mode

Parameter description: Specifies whether the pgxc_node system catalog can be modified when the database instance is in read-only mode.

Parameter type: Boolean.

Unit: none

Value range:

• on: The pgxc_node system catalog can be modified.
• off: The pgxc_node system catalog cannot be modified.

Default value: on

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 in Table 2. The modification takes effect only after the CM Agent is restarted.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

unix_socket_directory

Parameter description: Specifies the directory location of the Unix socket.

Parameter type: string.

Unit: none

Value range: valid path of a directory.

Default value: ""

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

enable_dcf

Parameter description: Specifies the status of the DCF mode.

Parameter type: Boolean.

Unit: none

Value range:

• on: The DCF mode is enabled.

• off: The DCF mode is disabled.

Default value: off

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

disaster_recovery_type

Parameter description: Specifies the type of the DR relationship between the primary and standby database instances.

Parameter type: integer.

Unit: none

Value range: 0 to 2

• 0: No DR relationship is established.
• 1: The Dorado DR relationship is established.
• 2: The streaming replication-based DR relationship is established.

Default value: 0

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

enable_e2e_rto

Parameter description: Specifies whether to enable the E2E RTO function. After this function is enabled, the hang-up detection period and network detection timeout interval are shortened. The CM can reach the E2E RTO indicator (RTO for a single instance ≤ 10s; RTO for combined faults ≤ 30s).

Parameter type: integer.

Unit: none

Value range: 0 to 1

• 0: The E2E RTO function is disabled.
• 1: The E2E RTO function is enabled.

Default value: 0

Setting method: This parameter is a CM parameter. For details about how to modify this parameter, see method 1 and method 2 in Table 2.

Setting suggestion: Retain the default value. You can adjust the value as required.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

thread_effective_time

Parameter description: Specifies the timeout interval for a round of thread running. If the timeout occurs, the thread is suspended and automatically exits.

Parameter type: integer.

Unit: second

Value range: 0 to 1200. The value 0 indicates that the thread monitoring capability is disabled.

Default value: 60

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: You are advised not to change the parameter value. To adjust the value, contact Huawei technical support.

Risks and impacts of improper settings: If the value is too large or too small, false negative and false positive may occur during fault detection.

ping_fault_kill_inst_timeout

Parameter description: Specifies the timeout interval for restarting a primary DN after the primary DN cannot ping all standby DNs.

Parameter type: integer.

Unit: second

Value range: 0 to 1000. The value 0 indicates that the ping fault processing capability is disabled.

Default value: 30

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large or too small, false negative and false positive may occur during fault detection.

high_cpu_threshold

Parameter description: Specifies the CPU usage threshold. When the CPU usage exceeds the threshold, the CM Agent prints CPU usage information in logs at a specified check interval (1s by default).

Parameter type: integer.

Unit: %

Value range: 0 to 100

Default value: 95

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

high_mem_threshold

Parameter description: Specifies the memory usage threshold. When the memory usage exceeds the threshold, the CM Agent prints memory usage information in logs at a specified check interval (1s by default).

Parameter type: integer.

Unit: %

Value range: 0 to 100

Default value: 95

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

high_disk_threshold

Parameter description: Specifies the disk I/O threshold. When the I/O exceeds the threshold, the CM Agent prints I/O information in logs at a specified check interval (1s by default). The iostat -xm information is recorded in the system_stat log file for 10 consecutive times at an interval of 1s.

Parameter type: integer.

Unit: %

Value range: 0 to 100

Default value: 95

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

sys_check_interval

Parameter description: Specifies the system resource check period, that is, the interval for checking the CPU, memory, and disk I/O usage. The value 0 indicates that the check is disabled.

Parameter type: integer.

Unit: second

Value range: 0 to 10

Default value: 1

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large, alarms may not be reported in a timely manner.

asyn_log_enable

Parameter description: Specifies whether to enable asynchronous logging. After this parameter is enabled, the CM Agent starts asynchronous logging.

Parameter type: Boolean.

Unit: none

Default value: on

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If this parameter is disabled, logs may be lost.

asyn_log_max_buf_size

Parameter description: Specifies the size of the asynchronous log buffer. When asynchronous logs are stacked and the stacked logs exceed the buffer size, subsequent logs cannot be recorded.

Parameter type: integer.

Unit: KB

Value range: 1 to 1048576

Default value: 1024

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Adjust the value based on the memory and hard disk size.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

asyn_log_fault_solution

Parameter description: Specifies the asynchronous log processing solution after a log disk fault is identified. When the CM detects that a log disk is faulty or the asynchronous log buffer overflows, the CM processes asynchronous logs based on the configuration.

Parameter type: integer.

Unit: none

Value range: 0 to 2

• 0: No extra processing is performed on logs. All logs are retained in the buffer until the buffer size reaches the upper limit. After the buffer size reaches the upper limit, no more logs are recorded.
• 1: Logs are filtered. After a log disk fault is identified, only key logs, alarms, and logs at the ERROR level or higher are saved to the buffer until the buffer size reaches the upper limit. After the buffer size reaches the upper limit, no more logs are recorded.
• 2: Logs are discarded. After a log disk fault is identified, only key logs and alarms are saved to the buffer until the buffer size reaches the upper limit. After the buffer size reaches the upper limit, no more logs are recorded.

Default value: 0

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Adjust the value based on the memory and hard disk size.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

disk_check_hung_timeout

Parameter description: Specifies the timeout interval for a disk I/O hang. When a single disk I/O check exceeds the timeout interval, the disk I/O hang occurs. The value 0 indicates that the disk hang check is disabled.

Parameter type: integer.

Unit: second

Value range: 0 to 1000

Default value: The default value is 20. If you cannot determine whether the detected disk is striped during installation, the default value is changed to 60.

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large or too small, false negative and false positive may occur during fault detection.

disk_check_block_timeout

Parameter description: If file operations such as open are blocked due to certain reasons in the file system and the blocking duration exceeds the value of this parameter, the system determines that the disk is faulty. If this parameter is set to 0, the determination is disabled.

Parameter type: integer.

Unit: second

Value range: 0 to 1000

Default value: 60

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large or too small, false negative and false positive may occur during fault detection.

disk_check_interval

Parameter description: Specifies the traffic of disk I/O hang check, that is, the minimum duration within which specified data needs to be written. The default check interval is 5 seconds. The value 0 indicates that the disk check is disabled.

Parameter type: integer.

Unit: second

Value range: 0 to 1000

Default Value: 5

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Improper settings may cause inaccurate fault detection and delayed fault rectification.

disk_check_io_size

Parameter description: Specifies the disk I/O hang check traffic, that is, the size of data written to the disk within the check duration. This is an I/O operation directly performed on the disk. By default, 512-byte data is written. If the detected disk is striped, the default value is changed to 262144 bytes (256 KB) during installation. A maximum of 1 GB data can be written. The value 0 indicates that the disk hang check is disabled. Disk detection has a whitelist, including the CM/DN data directory, disk where the log directory resides, and disk where the user-defined tablespace directory resides.

Parameter type: integer.

Unit: byte

Value range: 0 to 1073741824

Default value: 512

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Improper settings may cause inaccurate fault detection and delayed fault rectification.

process_unhealthy_alarm_time

Parameter description: Specifies the detection timeout interval for triggering the process status alarm. When a process is in an abnormal state (D, T, or Z) for a long time exceeding the value of this parameter, a process status alarm is triggered.

Parameter type: integer.

Unit: second

Value range: 0 to 2147483647. The value 0 indicates that this function is disabled.

Default value: 50

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large or too small, false negative and false positive may occur during fault detection.

enable_tblspc_disk_check

Parameter description: Specifies whether to enable the tablespace disk check function.

Parameter type: Boolean.

Unit: none

Value range:

• on: The tablespace disk check is enabled. That is, the disk where the tablespace is located is hung and the corresponding DN is stopped.
• off: The tablespace disk check function is disabled.

Default value: on

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then restart the database instance for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

max_network_package_loss

Parameter description: Checks the packet loss rate between the primary and standby DNs. If the packet loss rate of the primary DN exceeds the threshold, a restart is triggered.

Parameter type: integer.

Unit: %

Value range: 0 to 99. The value 0 indicates that this function is disabled.

Default value: 30

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too large, faults may not be rectified in a timely manner.

enable_auto_start

Parameter description: Specifies whether CM Agent automatically starts DNs and CNs.

Parameter type: integer.

Unit: none

Value range: 0 to 1

• 0: The automatic startup function is disabled.
• 1: The automatic startup function is enabled.

Default value: 1

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

enable_check_az_network

Parameter description: Specifies whether to enable AZ-level data plane network detection.

Parameter type: Boolean.

Unit: none

Value range:

• on: AZ-level data plane network detection is enabled.
• off: AZ-level data plane network detection is disabled.

Default value: on

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If this parameter is disabled, the fault detection function deteriorates.

expect_stop_az_name

Parameter description: Specifies the name of the AZ to be stopped by the AZ-level network detection function.

Parameter type: string.

Unit: none

Value range: name of an existing AZ in the environment. If this parameter is left empty, instances in the AZ opposite to the primary CM Server are stopped.

Default value: ""

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.

check_az_network_concurrency

Parameter description: Specifies the number of concurrent AZ-level network detection tasks.

Parameter type: integer.

Unit: none

Value range: 1 to 10

Default value: 2

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: If the value is too small, CM fault detection and recovery cannot be performed in a timely manner. If the value is too large, the CPU load increases.

cm_hadr_process_type

Parameter description: Specifies the DR process ID.

Value type: enumerated type.

Unit: none

Value range:

• none: There is no process.
• failover: The database instance for DR is switched to primary.
• switchover_promote: The process of promoting the standby database instance for DR to the primary database instance during the primary/standby database instance switchover.
• switchover_demote: The process of demoting the primary database instance to the standby database instance for DR during the primary/standby instance switchover.

Default value: none

Setting method: Refer to the set cm parameters table in "Unified Database Management Tool > cm_ctl Tool Introduction" in Tool Reference. Then run the reload command for the settings to take effect.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Change the parameter value after you fully understand the parameter meaning and test the parameter.