Unified Database Management Tool

The cluster manager (CM) is a database management module. It supports customized resource monitoring and provides capabilities such as monitoring of the primary/standby database status, network communication faults, file system faults, and automatic primary/standby switchover upon faults. It also provides various database management capabilities, such as starting and stopping nodes and instances, querying database instance status, performing primary/standby switchover, and managing logs.

Note that in a scenario where there are one primary node and one standby node, the CM supports only basic capabilities, such as installation, startup, stop, and detection.

Features

cm_agent

cm_agent is a database management component deployed on each database host. It is used to start, stop, and monitor database instance processes.

It has the following functions:

• It starts and stops the instance processes deployed on the local host when the database instance is started or stopped.
• It monitors the instance status on the local host and sends the status to the CM server.
• It runs the commands delivered by the CM server after arbitration.

Command description:

• Common options:

  • -V, --version

    Prints the cm_agent version information and exits.

  • -?, -h,--help

    Displays help information about cm_agent command parameters and exits.

• Locations where the log information is recorded:

  • 0

    Recorded in specified log files.

  • 1

    Recorded in the syslog file.

  • 2

    Recorded in specified log files.

  • 3

    Empty file, that is, no log information is recorded.

• Startup modes:

  • normal

    Startup in normal mode.

  • abnormal

    Startup in abnormal mode.

cm_server

cm_server is a component used for managing database instances and arbitrating instances. It has the following functions:

• Receives the status of each database instance from cm_agent on each node.
• Allows you to query the overall status of the database instances.
• Monitors instance status changes and delivers arbitration commands.

Command description:

• Common options:

  • -V, --version

    Prints the cm_server version information and exits.

  • -?, -h,--help

    Displays help information about cm_server command parameters and exits.

• Locations where the log information is recorded:

  • 0

    Recorded in specified log files.

  • 1

    Recorded in the syslog file.

  • 2

    Recorded in specified log files.

  • 3

    Empty file, that is, no log information is recorded.

Introduction to the cm_ctl Tool

cm_ctl is a tool provided by MogDB to control database instance services. This tool is called by O&M personnel for automatic database instance service restoration. The cm_ctl tool provides the following functions:

• Starts database instance services, all the instances in an AZ, all instances on a single host, or a single instance process.
• Stops database instance services, all instances in an AZ, all instances on a single host, or instance processes on a single node.
• Restarts the logical database instance service.
• Queries the database instance status or the status of a single host.
• Switches over the primary and standby instances or resets the instance status.
• Rebuilds the standby node.
• Views the database instance configuration file.
• Sets the log level, the arbitration mode of cm_server when one primary and multiple standby database instances are deployed, and the switchover mode between AZs.
• Obtains the log level, the arbitration mode of cm_server when one primary and multiple standby database instances are deployed, and the switchover mode between AZs.
• Checks the status of an instance process.

Files related to the cm_ctl tool:

• cluster_manual_start

  This is a flag file for starting and stopping a database instance. This file is stored in $GAUSSHOME**/bin**, where GAUSSHOME is an environment variable. When the database instance is started, the cm_ctl tool deletes the file. When the database instance is stopped, the cm_ctl tool generates the file and writes the stop mode to the file.

• instance_manual_start_X (X indicates the instance ID.)

  This is a flag file for starting and stopping a single instance. This file is stored in $GAUSSHOME**/bin**, where GAUSSHOME is an environment variable. When the instance is started, the cm_ctl tool deletes the file. When the instance is stopped, the cm_ctl tool generates the file and writes the stop mode to the file.

cm_ctl constraints:

• In cluster mode, the cm_ctl tool instead of the gs_ctl tool is used to switch the database role.

Command Description

Table 1 Parameters for option

Parameter	Description
start	Starts the database instance service, all instances on a single host, instance processes on a single node, or the entire AZ when one primary database and multiple standby databases are deployed.
switchover	Switches over the primary and standby database instances when one primary database and multiple standby databases are deployed. In DCF mode, the -n NODEID and -D DATADIR parameters are not supported.
finishredo	Stops the playback on all standby nodes, and forcibly promotes one of the shards to primary. CAUTION: Setting this parameter is a high-risk operation. Exercise caution when performing this operation.
build	Rebuilds a standby instance.
check	Checks the running status of an instance process. You are not advised to use this parameter.
stop	Stops the database instance service, all instances on a single host, or the instance processes on a single node when one primary database and multiple standby databases are deployed.
query	Queries the database instance status or the status of a single host when one primary database and multiple standby databases are deployed.
view	Views the database instance configuration file.
set	Sets the log level, the arbitration mode of cm_server when one primary database and multiple standby databases are deployed, the switchover mode between AZs, and the promotion mode to primary of cm_server.
set --param	Sets CM parameters. By default, parameters on all nodes are set. You can also use the -n parameter to set parameters on a node.
get	Obtains the log level, the arbitration mode of cm_server when one primary database and multiple standby databases are deployed, and the switchover mode between AZs.
setrunmode	Sets the number of DCF votes in DCF deployment mode. This parameter is used for forcible DCF startup.
changerole	Changes the primary role to passive or follower in the DCF mode.
changemember	Changes the attributes of a DCF node in DCF mode, including the role, logical group, and election priority of the node.
reload	Loads the static configuration file of a database instance online. You are not advised to use this parameter.
reload --param	Loads CM parameters that can take effect dynamically. Some parameters cannot be reloaded and can take effect only after the CM is restarted.
list	Lists all parameters of cm_agent or cm_server.
encrypt	Encrypts an entered password. The password can contain 8 to 15 characters and must contain at least three types of the following characters: digits, letters, and symbols.
ddb	Runs the DCC command in DCC mode.
switch	Switches to the DDB mode. NOTE: Currently, MogDB can be switched only to the DCC mode.

Table 2 Common parameters

Parameter	Description
-D DATADIR	Specifies the instance data directory.
-l FILENAME	Outputs the result to a specified file.
-n NODEID	Specifies a node.
-z AVAILABILITY_ZONE	Specifies an AZ name.
-t SECS	Specifies a timeout period.
-V, --version	Prints the cm_ctl version and exits.
-?, -h,--help	Displays help information about cm_ctl command parameters and exits.

Table 3 Parameters for switchover

Parameter	Description
-a	Restores nodes to their initial status. NOTE: Switchover is performed for maintenance. Before a switchover, ensure that the cluster is running properly, all services are stopped, and the pgxc_get_senders_catchup_time() view shows no ongoing catchup between the primary and standby nodes.
-A	Switches all node instances from primary to standby.
-f	Specifies that a switchover of the -f type is performed. NOTE: Switchover is performed for maintenance. Before a switchover, ensure that the cluster is running properly, all services are stopped, and the pgxc_get_senders_catchup_time() view shows no ongoing catchup between the primary and standby nodes. Usage: cm_ctl switchover -n NODEID -D DATADIR -f.

Table 4 Parameters for build

Parameter	Description
-f	Forcibly rebuilds a standby node
-b full	Performs a full build. If this parameter is not specified, automatic build is performed for the deployment mode of one primary database instance and multiple standby database instances. auto build: calls the incremental build first and calls the full build after the incremental build fails.
-c	Rebuilds cm_server (by copying the DCC data directory on the primary node to the specified node. This method is applicable only to the scenario where there are one primary node and one standby node.)

Table 5 Parameters for check

Parameter	Description
-B BINNAME	Specifies the name of a process, which can be cm_agent, gaussdb, or cm_server.
-T DATAPATH	Specifies the instance data directory.

Table 6 Parameters for stop

Parameter	Description
-m SHUTDOWN-MODE	Specifies the stop mode. The options are as follows: smart (s): The database instance exits after user services end. fast (f): The database instance exits without waiting for the user service to end. immediate (i): The database instance is forced to exit without waiting for the user service to end.

Table 7 Parameters for query

Parameter	Description
-s	Displays instances that result in unbalanced primary and standby instance quantity on each host. NOTE: The -s parameter must be used together with -v and -C so that instances that result in unbalanced primary and standby instance quantity on each host can be displayed in pairs. When using -s, -C and -v must be specified.
-C	Displays the database instance status in pairs based on the primary and standby relationship. NOTE: The -C parameter must be used together with -v to display detailed database instance status information in pairs based on the primary and standby relationship. When using -C, -v must be specified.
-v	Displays the detailed database instance status. NOTE: A database instance can be in any of the following states: Normal: indicates that the database instance is available and the data is backed up. All the processes are running and the primary and standby relationship is normal. Degraded: The database instance is available, but data is not backed up. Unavailable: The database instance is unavailable.
-d	Displays the instance data directory. NOTE: The -d parameter must be used together with the -v and -C parameters.
-i	Displays the IP addresses of physical nodes. NOTE: The -i parameter must be used together with the -v and -C parameters.
-F	Displays the fenced UDF status of each node. NOTE: The -F parameter must be used together with the -v and -C parameters to display the fenced UDF status of each node. When the -F parameter is used, the -C and -v parameters must be specified.
-z ALL	Displays the AZ name of a database instance. NOTE: The -z parameter must be used together with -v and -C and be followed by ALL.
-r	Displays the redo status of the standby node. NOTE: When using -r, you must specify the -v parameter.
-g	Displays information about cluster backup and restoration.
-x	Displays all abnormal database instances. NOTE: The -x parameter must be used together with the -v and -C parameters.
-S	Displays the status check result when a database instance is started. NOTE: The -S parameter must be used together with the -v and -C parameters to display the database instance status check result. The states are as follows: Normal: The database instance is available and the data is backed up. All the processes are running and the primary and standby relationship is normal. Degraded: The database instance is available, but data is not backed up. Unavailable: The database instance is unavailable.
--minorityAz	Queries the CMS in a specified AZ. NOTE: This parameter ignores the CMS nodes in non-specified AZs and can improve the query speed in few scenarios.
-p	Displays the ports of all database instance nodes. NOTE: The -p parameter must be used together with the -v and -C parameters.

Table 8 Parameters for set

Parameter	Description
--log_level=LOG_LEVEL	Sets the log level of the primary cm_server. Six log levels are included: DEBUG5, DEBUG1, WARNING, LOG, ERROR, and FATAL, in an ascending order in terms of log print level. The higher the log level, the less the log print information.
--cm_arbitration_mode=ARBITRATION_MODE	Sets the arbitration mode of cm_server when one primary and multiple standbys are deployed. There are two modes: MAJORITY and MINORITY. MAJORITY indicates the majority mode, and MINORITY indicates the minority mode. MogDB does not support the MINORITY mode. This parameter can be set to MINORITY but it does not take effect.
--cm_switchover_az_mode= SWITCHOVER_AZ_MODE	Enables/Disables automatic switchover between AZs when one primary and multiple standbys are deployed. There are two modes: NON_AUTO and AUTO. NON_AUTO indicates the non-automatic switchover mode, and AUTO indicates the automatic switchover mode. In AUTO mode, the primary cm_server automatically controls the node instance switchover between AZ1 and AZ2.
--cmsPromoteMode=CMS_PROMOTE_MODE -I INSTANCEID	Sets the promotion mode to primary of cm_server. There are two modes: AUTO and PRIMARY_F. AUTO indicates that the promotion mode to primary is automatically selected. PRIMARY_F indicates that the node specified by -I is forcibly promoted to primary, regardless of whether there is a primary node. Therefore, multiple primary cm_server may exist.

**Table 9** Parameters for set cm

Parameter	Description
--param	Specifies the CM parameters to be set. If this parameter is not specified, the CM parameters cannot be set.
--agent | --server	Specifies whether to set the cm_server or cm_agent parameters. This parameter is mandatory.
-k parameter="value"	Specifies the parameters and parameter values to be set. Only existing parameters can be set. Parameters cannot be added or deleted.

Table 10 Parameters for get

Parameter	Description
--log_level=LOG_LEVEL	Obtains the log level of the primary cm_server. Six log levels are included: DEBUG5, DEBUG1, WARNING, LOG, ERROR, and FATAL, in an ascending order in terms of log print level. The higher the log level, the less the log print information.
--cm_arbitration_mode=ARBITRATION_MODE	Obtains the arbitration mode of cm_server when one primary and multiple standbys are deployed. There are two modes: MAJORITY and MINORITY. MAJORITY indicates the majority mode, and MINORITY indicates the minority mode. The MINORITY mode is applicable to the scenario where one primary database and multiple standby databases are deployed and only AZ3 is alive. In this case, cm_server can perform arbitration properly. In other modes, after the arbitration mode is set to MINORITY, the CM automatically changes the arbitration mode to MAJORITY to ensure the normal running of the cluster. The MAJORITY mode is applicable to the scenario where one primary database and multiple standby databases are deployed and the number of alive components (cm_server and nodes) is greater than half of the total. In normal cases, the database instance is in MAJORITY mode by default. CAUTION: MogDB does not support the MINORITY mode.
--cm_switchover_az_mode =SWITCHOVER_AZ_MODE	Obtains the automatic switchover mode between AZs when one primary and multiple standbys are deployed. There are two modes: NON_AUTO and AUTO. NON_AUTO indicates the non-automatic switchover mode, and AUTO indicates the automatic switchover mode. In AUTO mode, the primary cm_server automatically controls the node instance switchover between AZ1 and AZ2.

Table 11 Parameters for view

Parameter	Description
-v	Displays the static configuration details of all nodes in the database instance. NOTE: Compared with the cm_ctl view command, cm-server and node component IDs (for example, cmseverInstanceID and datanodeInstanceID) are added to the output of -v.
-N	Displays only the static configuration of the local node, that is, information about the node where the cm_ctl view command is executed. N indicates "native".

Table 12 Parameters for setrunmode

Parameter	Description	Value Range
--xmode	Specified the DCF running mode.	normal: normal mode. minority: minority mode. In this mode, --votenum is used to specify the number of votes.
--votenum	Specifies the number of votes for a DCF minority run.	The value is a positive integer and cannot be greater than the total number of DCF copies.

Table 13 Parameters for changerole

Parameter	Description	Value Range
--role	Changes the primary role to passive or follower in the DCF mode.	passive: passive role follower: follower role

Table 14 Parameters for changemember

Parameter	Description	Value Range
--role	Changes the primary role to passive or follower in the DCF mode.	passive: passive role follower: follower role
--group	Changes the value of group in DCF mode.	0–2147483647
--priority	Changes the value of priority in DCF mode.	0–2147483647

Table 15 Parameters for start

Parameter

Description

--cm_arbitration_mode=ARBITRATION_MODE

Obtains the arbitration mode of cm_server when one primary and multiple standbys are deployed. There are two modes: MAJORITY and MINORITY. MAJORITY indicates the majority mode, and MINORITY indicates the minority mode. The MINORITY mode is applicable to the scenario where one primary database and multiple standby databases are deployed and only AZ3 is alive. In this case, cm_server can perform arbitration properly. In other modes, after the arbitration mode is set to MINORITY, the CM automatically changes the arbitration mode to MAJORITY to ensure the normal running of the cluster. The MAJORITY mode is applicable to the scenario where one primary database and multiple standby databases are deployed and the number of alive components (cm_server and nodes) is greater than half of the total. In normal cases, the database instance is in MAJORITY mode by default. CAUTION: MogDB does not support the MINORITY mode.

Table 16 Parameters for reload

Parameter	Description
--param	Specifies the CM parameters to be loaded. If this parameter is not specified, the CM parameters cannot be loaded.
--agent | --server	Specifies whether to dynamically load cm_server or cm_agent parameters.

Table 17 Parameters for list

Parameter	Description
--param	Specifies the CM parameters to be listed. This parameter is mandatory.
--agent | --server	Specifies the cm_server or cm_agent parameters to be listed. This parameter is mandatory.

Table 18 Parameters for encrypt

Parameter	Description
-M	Specifies the encryption type. The value can be server or client. The default value is server.
-D	Specifies the path of the encrypted password file.

Table 19 Parameters for switch

Parameter	Description
--ddb_type=[DDB]	Select the DDB mode to be switched to. (MogDB supports only the DCC mode.)
--commit	After the switchover, the database instance cannot be promoted to primary. You need to run the commit command to restore the database instance.
--rollback	Rolls back the switchover that fails.

**Table 20** Parameters for ddb

Parameter	Description
--put [key] [value]	Inserts a key-value pair to DCC. If the key-value pair already exists, the value corresponding to the key is changed.
--get [key]	Queries the value corresponding to the key in DCC.
--delete [key]	Deletes a specified key-value pair from DCC.
--prefix	You can add the prefix parameter after the get or delete operation to implement fuzzy query and deletion.
--cluster_info	Obtains the database instance information.
--leader_info	Obtains information about the primary node.
--help, -h	Displays the DCC command help information.
--version, -v	Displays DCC version information.

Command Reference

• Start an instance.

  cm_ctl start [-z AVAILABILITY_ZONE [--cm_arbitration_mode=ARBITRATION_MODE]] | [-n NODEID [-D DATADIR]] [-t SECS]

• Perform a switchover between primary and standby databases.

  cm_ctl switchover [-z AVAILABILITY_ZONE] | [-n NODEID -D DATADIR [-f]] | [-a] | [-A] [-t SECS]

• Stop the playback on all standby nodes, and forcibly promote one of the shards to primary.

  cm_ctl finishredo

• Rebuild the standby node.

  cm_ctl build -n NODEID -D DATADIR [-t SECS] [-f] [-b full]

• Check the running status of an instance process.

  cm_ctl check -B BINNAME -T DATAPATH

• Stop an instance.

  cm_ctl stop [[-z AVAILABILITY_ZONE] | [-n NODEID [-D DATADIR [-R]]]] [-t SECS] [-m SHUTDOWN-MODE]

• Query the cluster status.

  cm_ctl query [-z ALL] [-l FILENAME] [-v [-C [-s] [-S] [-d] [-i] [-F] [-x] [-p]] | [-r]] [-t SECS] [--minorityAz=AZ_NAME]

• View the cluster configuration file.

  cm_ctl view [-v | -N | -n NODEID] [-l FILENAME]

• Set parameters.

  cm_ctl set [--log_level=LOG_LEVEL] [--cm_arbitration_mode=ARBITRATION_MODE] [--cm_switchover_az_mode=SWITCHOVER_AZ_MODE]

• Set CM parameters.

  cm_ctl set --param --agent | --server [-n NODEID] -k PARAMETER="'value'"

• Obtain parameters.

  cm_ctl get [--log_level] [--cm_arbitration_mode] [--cm_switchover_az_mode]

• Set the number of DCF votes.

  cm_ctl setrunmode -n NODEID -D DATADIR  [[--xmode=normal] | [--xmode=minority --votenum=NUM]]

• Change the DCF role information.

  cm_ctl changerole [--role=PASSIVE | --role=FOLLOWER] -n NODEID -D DATADIR [-t SECS]

• Change the attributes of the DCF node.

  cm_ctl changemember [--role=PASSIVE | --role=FOLLOWER] [--group=xx] [--priority=xx] -n NODEID -D DATADIR [-t SECS]

• Dynamically load CM parameters.

  cm_ctl reload --param [--agent | --server]

• List all CM parameters.

  cm_ctl list --param [--agent | --server]

• Perform encryption.

  cm_ctl encrypt [-M MODE] -D DATADIR

• Run the DCC command.

  cm_ctl ddb DCC_CMD
  Set: cm_ctl ddb --put [key] [value]
  Delete: cm_ctl ddb --delete [key]
  View DCC command help information: cm_ctl ddb --help

• Run the switch ddb command.

  cm_ctl switch [--ddb_type=[DDB]] [--commit] [--rollback]

Security Design

Procedure for Manually Replacing Certificates

• Create a self-signed certificate.

  For details about how to create a self-signed certificate, see Generating Certificates.

  To protect the private key password, use the cm encrypt tool. For details, see Introduction to the cm_ctl Tool.

  Copy Codecm_ctl encrypt [-M MODE] -D DATADIR

  1. Generate the server key factors server.key.cipher and server.key.rand.

     Copy Codecm_ctl encrypt -M server -D DATADIR
     please enter the password: (The password must be the same as the protection password of the server private key.)

  2. Generate the client key factors client.key.cipher and client.key.rand.

     Copy Codecm_ctl encrypt -M client -D DATADIR
     please enter the password: (The password must be the same as the protection password of the client private key.)

Certificate Usage Guide

1. To use the certificate, you need to set the cm_server parameter to on (The default value is off).

   Copy Codecm_ctl set --param --server -k enable_ssl="on"

2. The certificate file must exist in $GAUSSHOME**/share/sslcert/cm** on all nodes. After the certificate is replaced, restart the cluster for the certificate to take effect.

   Required certificate files include server.crt, server.key, client.crt, client.key, cacert.pem, server.key.cipher, server.key.rand, client.key.cipher, and client.key.rand.

   The permission on the root certificate, key, certificate, and encrypted key file should be 400. If the permission does not meet the requirements, SSL cannot be used.

   • chmod 400 cacert.pem
   • chmod 400 server.crt
   • chmod 400 server.key
   • chmod 400 server.key.cipher
   • chmod 400 server.key.rand
   • chmod 400 client.crt
   • chmod 400 client.key
   • chmod 400 client.key.cipher
   • chmod 400 client.key.rand

3. The certificate validity period is checked every day, which can be set through ssl_cert_expire_check_interval. An alarm is generated when the certificate is about to expire in 90 days, which can be set through ssl_cert_expire_alert_threshold. (For details about the parameter, see ssl_cert_expire_alert_threshold.)

CM Parameters

You can view cm_agent parameters in the cm_agent.conf file in the cm_agent data directory and cm_server parameters in the cm_server.conf file in the cm_server data directory.

Parameters Related to cm_agent

log_dir

Parameter description: Specifies the directory where cm_agent logs are stored. It can be specified as an absolute path, or a path relative to $GAUSSLOG. When you set an absolute path using cm_ctl, the path must be included in quotation marks, for example, cm_ctl set --param --agent -k log_dir="'/log/dir'".

Value range: a string with up to 1024 characters. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: log, indicating that the cm_agent logs are generated in the CM directory in $GAUSSLOG.

log_file_size

Parameter description: Specifies the size of a log file. If the size of the cm_agent-xx-current.log file exceeds the specified size, a new log file is created to record log information.

Value range: an integer, in the range [0,2047]. The actual value range is [1,2047]. The unit is MB. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 16 MB

log_min_messages

Parameter description: Specifies which message levels are written to the cm_agent log. A higher level covers the messages of all the lower levels. The lower the level is, the fewer messages will be written into the log.

Value range: enumerated type. Valid values are debug5, debug1, warning, error, log, and fatal (case-insensitive). Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: warning

incremental_build

Parameter description: Specifies whether a standby node is incrementally built. If this parameter is enabled, a standby node is incrementally rebuilt. Otherwise, a standby node is fully rebuilt.

Value range: Boolean. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

• on, yes, true, or 1: A standby node is incrementally rebuilt.
• off, no, false, or 0: A standby node is fully rebuilt.

Default value: on

security_mode

Parameter description: Specifies whether nodes are started in secure mode. If this parameter is enabled, nodes are started in secure mode. Otherwise, nodes are started in non-secure mode.

Value range: Boolean. The modification of this parameter takes effect dynamically. For details about how to modify the parameter, see Parameters for set cm.

• on, yes, true, or 1: Nodes are started in secure mode.
• off, no, false, or 0: Nodes are started in non-secure mode.

Default value: off

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.

Value range: a non-negative integer, in the range [0,4294967295]. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 0

alarm_component

Parameter description: Specifies the position of the alarm component that handles alarms if the first mode is used. When you set an absolute path using cm_ctl, the path must be included in quotation marks (''), for example, cm_ctl set --param --agent -k alarm_component="'/alarm/dir'".

Value range: a string with up to 1024 characters. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

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

alarm_report_interval

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

Value range: a non-negative integer, in the range [0,2147483647] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1

agent_heartbeat_timeout

Parameter description: Specifies the time to wait before the cm_server heartbeat times out.

Value range: an integer, in the range [2,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 5

agent_connect_timeout

Parameter description: Specifies the time to wait before the attempt of cm_agent to connect to cm_server times out.

Value range: an integer, in the range [0,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1

agent_connect_retries

Parameter description: Specifies the number of times cm_agent tries to connect to cm_server.

Value range: an integer, in the range [0,2147483647]. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 15

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 kills all instances on the node.

Value range: an integer, in the range [0,2147483647]. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

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

agent_report_interval

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

Value range: an integer, in the range [0,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1

alarm_report_max_count

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

Value range: a non-negative integer, in the range [1,2592000]. The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1

agent_check_interval

Parameter description: Specifies the interval at which cm_agent queries the status of instances.

Value range: an integer, in the range [0,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 2

enable_log_compress

Parameter description: Specifies whether to enable log compression.

Value range: Boolean. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

• on, yes, true, or 1: Log compression is allowed.
• off, no, false, or 0:Log compression is not allowed.

Default value: on

process_cpu_affinity

Parameter description: Specifies whether to bind a primary node process to a CPU core before starting the process. If this parameter is set to 0, core binding is not performed. If it is set to another value, core binding is performed, and the number of physical CPU cores is 2n. Restart the database and cm_agent for any modification of this parameter to take effect. Only ARM is supported. For details about how to modify the parameter, see Parameters for set cm.

Value range: an integer, in the range [0,2].

Default value: 0

enable_xc_maintenance_mode

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

Value range: Boolean. The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

• on, yes, true, or 1: The function of modifying the pgxc_node system catalog is enabled.
• off, no, false, or 0: The function of modifying the pgxc_node system catalog is disabled.

Default value: on

log_threshold_check_interval

Parameter description: Specifies the interval for compressing and clearing CM logs. The logs are compressed and cleared every 1800 seconds.

Application scope: $GAUSSLOG**/cm/cm_ctl**, $GAUSSLOG**/cm/cm_server**, files in the $GAUSSLOG**/cm/om_monitor** directory and log files prefixed with cm_agent-, system_call-, and system_alarm- in the $GAUSSLOG**/cm/cm_agent** directory

Value range: an integer, in the range [0,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1800

log_max_size

Parameter description: Specifies the maximum size of CM logs. When the total size of CM logs exceeds (value of log_max_size x 95⁄100) MB, historical compressed logs are deleted in sequence based on the log generation time until the total size is less than (value of log_max_size x 95⁄100) MB.

Application scope: $GAUSSLOG**/cm/cm_ctl**, $GAUSSLOG**/cm/cm_server**, files in the $GAUSSLOG**/cm/om_monitor** directory and log files prefixed with cm_agent-, system_call-, and system_alarm- in the $GAUSSLOG**/cm/cm_agent** directory

Value range: an integer, in the range [0,2147483647] (unit: MB). Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 10240

log_max_count

Parameter description: Specifies the maximum number of CM log files that can be stored. When the total number of CM log files exceeds the value of this parameter, compressed logs that have been stored for days longer than those specified by log_saved_days are deleted based on the name of the compressed log file.

Application scope: $GAUSSLOG**/cm/cm_ctl**, $GAUSSLOG**/cm/cm_server**, files in the $GAUSSLOG**/cm/om_monitor** directory and log files prefixed with cm_agent-, system_call-, and system_alarm- in the $GAUSSLOG**/cm/cm_agent** directory

Value range: an integer, in the range [0,10000]. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 10000

log_saved_days

Parameter description: Specifies the number of days for storing compressed CM log files. If the number of compressed CM log files exceeds the value of this parameter and the total number of CM log files exceeds the value of log_max_count, the compressed log files are deleted.

Application scope: $GAUSSLOG**/cm/cm_ctl**, $GAUSSLOG**/cm/cm_server**, files in the $GAUSSLOG**/cm/om_monitor** directory and log files prefixed with cm_agent-, system_call-, and system_alarm- in the $GAUSSLOG**/cm/cm_agent** directory

Value range: an integer, in the range [0,1000]. (unit: day). Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 90

agent_phony_dead_check_interval

Parameter description: Specifies the interval at which cm_agent checks whether a process is suspended.

Value range: an integer, in the range [0,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 10

unix_socket_directory

Parameter description: Specifies the directory location of the Unix socket. When you set an absolute path using cm_ctl, the path must be included in quotation marks (''), for example, cm_ctl set --param --agent -k unix_socket_directory="'/unix/dir'".

Value range: a string with up to 1024 characters. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: ''

dilatation_shard_count_for_disk_capacity_alarm

Parameter description: Specifies the number of shards to be added in the scale-out scenario. This parameter is used to calculate the threshold for reporting a disk capacity alarm.

Value range: an integer, in the range [0,2147483647]. If this parameter is set to 0, the disk scale-out alarm is not reported. If this parameter is set to a value greater than 0, the disk scale-out alarm is reported and the threshold is calculated based on the number of shards specified by this parameter. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1

enable_dcf

Parameter description: Specifies the status of the DCF mode.

Value range: Boolean. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

• on, yes, true, or 1: The DCF function is enabled.
• off, no, false, or 0:The DCF function is disabled.

Default value: off

disaster_recovery_type

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

Value range: an integer, in the range [0,2]. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

• 0 indicates that no DR relationship is established.
• 1 indicates that the OBS DR relationship is established.
• 2 indicates that the streaming DR relationship is established.

Default value: 0

agent_backup_open

Parameter description: Specifies whether to enable the DR mode. After the DR mode is enabled, the CM runs in DR mode.

Value range: an integer, in the range [0,2]. Any modification of this parameter takes effect only after cm_agent is restarted. For details about how to modify the parameter, see Parameters for set cm.

• 0 indicates that no DR relationship is established.
• 1 indicates that the OBS DR relationship is established (not supported later versions).
• 2 indicates that the streaming DR relationship is established.

Default value: 0

Parameters Related to cm_server

log_dir

Parameter description: Specifies the directory where cm_server logs are stored. It can be specified as an absolute path, or a path relative to $GAUSSLOG. When you set an absolute path using cm_ctl, the path must be included in quotation marks, for example, cm_ctl set --param --server -k log_dir="'/log/dir'".

Value range: a string with up to 1024 characters. Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: log, indicating that the cm_server logs are generated in the CM directory in $GAUSSLOG.

log_file_size

Parameter description: Specifies the size of a log file. If the size of the cm_server-xx-current.log file exceeds the specified size, a new log file is created to record log information.

Value range: an integer, in the range [0,2047]. The actual value range is [1,2047]. The unit is MB. Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 16 MB

log_min_messages

Parameter description: Specifies the message levels to be written to the cm_server log. A higher level covers the messages of all the lower levels. The lower the level is, the fewer messages will be written into the log.

Value range: enumerated type. Valid values are debug5, debug1, log, warning, error, and fatal (case-insensitive). Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: warning

thread_count

Parameter description: Specifies the number of threads in the cm_server thread pool.

Value range: an integer, in the range [2,1000]. Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1000

instance_heartbeat_timeout

Parameter description: Specifies the time to wait before the instance heartbeat times out.

Value range: an integer, in the range [1,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 6

instance_failover_delay_timeout

Parameter description: Specifies the delay in cm_server failover after the primary cm_server breakdown is detected.

Value range: an integer, in the range [0,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 0

cmserver_ha_connect_timeout

Parameter description: Specifies the time to wait before the connection between the primary cm_server and standby cm_server times out.

Value range: an integer, in the range [0,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 2

cmserver_ha_heartbeat_timeout

Parameter description: Specifies the time to wait before the heartbeat between the primary cm_server and standby cm_server times out.

Value range: an integer, in the range [1,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 6

cmserver_ha_status_interval

Parameter description: Specifies the interval between synchronizations of primary cm_server and standby cm_server status.

Value range: an integer, in the range [1,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1

cmserver_self_vote_timeout

Parameter description: Specifies the timeout interval for cm_server to vote for each other. This parameter is a legacy parameter and does not take effect.

Value range: an integer, in the range [0,2147483647] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 6

phony_dead_effective_time

Parameter description: Specifies the maximum number of times a database node is detected as a zombie. If the number of times the node is detected as a zombie is greater than the specified value, a process on the node is considered to be a zombie and will be restarted.

Value range: an integer, in the range [1,2147483647]. Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 5

cm_server_arbitrate_delay_base_time_out

Parameter description: Specifies the basic delay duration for cm_server arbitration. If the primary cm_server is disconnected, the arbitration starts to be timed. If the disconnection duration exceeds the arbitration delay duration, a new primary cm_server will be selected. The arbitration delay duration is determined by the basic delay duration, the node index (server ID), and the incremental delay duration. The formula is as follows: Arbitration delay duration = Basic delay duration + Node index x Incremental delay duration

Value range: an integer, in the range [0,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 10

cm_server_arbitrate_delay_incremental_time_out

Parameter description: Specifies the incremental delay duration for cm_server arbitration. If the primary cm_server is disconnected, the arbitration starts to be timed. If the disconnection duration exceeds the arbitration delay duration, a new primary cm_server will be selected. The arbitration delay duration is determined by the basic delay duration, the node index (server ID), and the incremental delay duration. The formula is as follows: Arbitration delay duration = Basic delay duration + Node index x Incremental delay duration

Value range: an integer, in the range [0,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 3

alarm_component

Parameter description: Specifies the position of the alarm component that handles alarms if the first mode is used. For details about how to modify the parameter, see Parameters for set cm. When you set an absolute path using cm_ctl, the path must be included in quotation marks (''), for example, cm_ctl set --param --server -k alarm_component="'/alarm/dir'".

Value range: a string with up to 1024 characters. Any modification of this parameter takes effect only after cm_server is restarted.

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

alarm_report_interval

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

Value range: a non-negative integer, in the range [0,2147483647] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 3

alarm_report_max_count

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

Value range: a non-negative integer, in the range [1,2592000]. The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1

instance_keep_heartbeat_timeout

Parameter description: cm_agent periodically checks the instance status and reports the status to cm_server. If the instance status cannot be detected for a long time and the accumulated number of times exceeds the value of this parameter, cm_server delivers a command to cm_agent to restart the instance.

Value range: an integer, in the range [0,2147483647] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 40

az_switchover_threshold

Parameter description: If the failure rate of a node shard in an AZ (Number of faulty node shards/Total number of node shards x 100%) exceeds the specified value, automatic AZ switchover is triggered.

Value range: an integer, in the range [1,100]. The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 100

az_check_and_arbitrate_interval

Parameter description: Specifies the interval for checking the AZ status. If the status of an AZ is abnormal, automatic AZ switchover is triggered.

Value range: an integer, in the range [1,2147483647] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 2

az_connect_check_interval

Parameter description: Specifies the interval at which the network connection between AZs is checked.

Value range: an integer, in the range [1,2147483647] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 60

az_connect_check_delay_time

Parameter description: Specifies the delay between two retries to check the network connection between AZs.

Value range: an integer, in the range [1,2147483647] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 150

cmserver_demote_delay_on_etcd_fault

Parameter description: Specifies the interval at which cm_server is demoted to standby due to unhealthy ETCD.

Value range: an integer, in the range [1,2147483647] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 8

instance_phony_dead_restart_interval

Parameter description: Specifies the interval at which cm_agent restarts and kills a zombie database instance. The interval between two consecutive kill operations cannot be less than the value of this parameter. Otherwise, cm_agent does not deliver commands.

Value range: an integer, in the range [1800,2147483647] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 21600

enable_transaction_read_only

Parameter description: Specifies whether a database is in read-only mode.

Value range: Boolean values on, off, true, false, yes, no, 1, and 0 The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: off

datastorage_threshold_check_interval

Parameter description: Specifies the interval for checking the disk usage. This interval is specified by the user.

Value range: an integer, in the range [1,2592000] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 10

datastorage_threshold_value_check

Parameter description: Specifies the usage threshold of a read-only disk in a database. When the disk usage of the data directory exceeds the specified value, the database is automatically set to read-only mode.

Value range: an integer, in the range [1,99]. The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 85

max_datastorage_threshold_check

Parameter description: Specifies the maximum interval for checking the disk usage. After you modify the enable_transaction_read_only parameter, the system automatically checks whether the disk usage reaches the threshold at the specified interval.

Value range: an integer, in the range [1,2592000] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 43200

enable_az_auto_switchover

Parameter description: Specifies whether to enable automatic AZ switchover. If this parameter is set to 1, cm_server automatically switches over services among AZs. Otherwise, when a node is faulty, services will not be automatically switched to another AZ even if the current AZ is unavailable. You can run the switchover command to manually switch services to another AZ.

Value range: a non-negative integer. The value 0 indicates that automatic AZ switchover is disabled, and the value 1 indicates that automatic AZ switchover is enabled. The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1

cm_krb_server_keyfile

Parameter description: Specifies the location of the key file on the Kerberos server. The value must be an absolute path. The file is usually stored in the ${GAUSSHOME}/kerberos directory and the file extension is keytab. The file name is the same as the name of the user who runs the cluster. This parameter is used together with cm_auth_method. If the value of the cm_auth_method parameter is changed to gss, cm_krb_server_keyfile must also be set to the corresponding path correctly. Otherwise, the cluster status will be affected. When you set an absolute path using cm_ctl, the path must be included in quotation marks (''), for example, cm_ctl set --param --server -k cm_krb_server_keyfile="'/krb/dir'".

Value range: a string. Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: ${GAUSSHOME}/kerberos/{Username}.keytab. The default value does not take effect and is used only for reference.

switch_rto

Parameter description: Specifies the delay for the forcible startup of cm_server. When force_promote is set to 1 and a shard in the cluster does not have primary cm_server, the system starts timing. After the delay, the forcible startup logic starts to be executed.

Value range: an integer, in the range [60,2147483647] (unit: second). Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 600

force_promote

Parameter description: Specifies whether cm_server enables the forcible startup logic (that is, when the cluster status is unknown, ensure that the basic functions of the cluster are available at the cost of data loss). The value 0 indicates that forcible startup is disabled, and the value 1 indicates that forcible startup is enabled.

Value range: an integer, 0 or 1. Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 0

backup_open

Parameter description: Specifies whether to enable the DR cluster. After the DR cluster is enabled, the CM runs in DR cluster mode.

Value range: an integer, 0 or 1. Any modification of this parameter takes effect only after cm_server is restarted. This parameter cannot be enabled for non-DR clusters. For details about how to modify the parameter, see Parameters for set cm.

• 0: The DR cluster is disabled.
• 1: The DR cluster is enabled.

Default value: 0

enable_dcf

Parameter description: Specifies the status of the DCF mode.

Value range: Boolean. Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

• on, yes, true, or 1: The DCF function is enabled.
• off, no, false, or 0: The DCF function is disabled.

Default value: off

ddb_type

Parameter description: Specifies whether to switch between ETCD and DCC modes.

Value range: an integer. 0: specifies the ETCD mode; 1: specifies the DCC mode. Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1

NOTE: (MogDB supports only the DCC mode.)

enable_ssl

Parameter description: Specifies whether to enable SSL.

Value range: Boolean. After this function is enabled, the SSL certificate is used to encrypt communication. Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value:

• on, yes, true, or 1: SSL is enabled.

• off, no, false, or 0: SSL is disabled.

• Default value: off

  NOTICE: To ensure security, you are not advised to disable it. After this function is disabled, the CM does not use encrypted communication and all information is transmitted in plaintext, which may bring security risks such as eavesdropping, tampering, and spoofing.

ssl_cert_expire_alert_threshold

Parameter description: Specifies the SSL certificate expiration alarm time.

Value range: an integer, in the range [7,180] (unit: day). If the certificate expiration time is less than the value of this parameter, an alarm indicating that the certificate is about to expire is reported. The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 90

ssl_cert_expire_check_interval

Parameter description: Specifies the period for checking whether the SSL certificate expires.

Value range: an integer, in the range [0,2147483647] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 86400

ddb_log_level

Parameter description: Sets the DDB log level.

To disable the log function, set this parameter to NONE, which cannot be used together with the following log levels:

To enable the log function, set this parameter to one or a combination of the following log levels: RUN_ERR|RUN_WAR|RUN_INF|DEBUG_ERR|DEBUG_WAR|DEBUG_INF|TRACE|PROFILE|OPER. If two or more log levels are used together, separate them with vertical bars (|). The log level cannot be set to an empty string.

Value range: a string containing one or a combination of the following log levels: RUN_ERR|RUN_WAR|RUN_INF|DEBUG_ERR|DEBUG_WAR|DEBUG_INF|TRACE|PROFILE|OPER. The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: RUN_ERR|RUN_WAR|DEBUG_ERR|OPER|RUN_INF|PROFILE

ddb_log_backup_file_count

Parameter description: Specifies the maximum number of log files that can be saved.

Value range: an integer, in the range [1,100]. The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 10

ddb_max_log_file_size

Parameter description: Specifies the maximum number of bytes in a log.

Value range: a string with up to 1024 characters, in the range [1 MB,1000 MB]. The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 10M

ddb_log_suppress_enable

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

Value range: an integer. 0: disabled; 1: enabled. The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 1

ddb_election_timeout

Parameter description: Specifies the DCC election timeout period.

Value range: an integer, in the range [1,600] (unit: second). The modification of this parameter takes effect after reloading. For details about how to modify the parameter, see Parameters for set cm.

Default value: 3

coordinator_heartbeat_timeout

Parameter description: Specifies the heartbeat timeout that triggers the automatical removal of faulty nodes. The setting of this parameter takes effect immediately, and you do not need to restart cm_server. If this parameter is set to 0, faulty nodes are not automatically removed.

Value range: an integer. The unit is second. For details about how to modify the parameter, see Parameters for set cm.

Default value: 25

cluster_starting_aribt_delay

Parameter description: Specifies the time that cm_server waits for a static primary-to-primary switchover during cluster startup.

Value range: an integer. The unit is second. Any modification of this parameter takes effect only after cm_server is restarted. For details about how to modify the parameter, see Parameters for set cm.

Default value: 180

enable_e2e_rto

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

Value range: an integer, 0 or 1. 1: The function is enabled; 0: The function is disabled. For details about how to modify the parameter, see Parameters for set cm.

Default value: 0