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Meta Service configuration

Nebula Graph provides two initial configuration files for the Meta Service, nebula-metad.conf.default and nebula-metad.conf.production. Users can use them in different scenarios conveniently. The default file path is /usr/local/nebula/etc/.

Caution

  • It is not recommended to modify the value of local_config to false. If modified, the Nebula Graph service will first read the cached configurations, which may cause configuration inconsistencies between clusters and cause unknown risks.
  • It is not recommended to modify the configurations that are not introduced in this topic, unless you are familiar with the source code and fully understand the function of configurations.

How to use the configuration files

To use the initial configuration file, choose one of the above two files and delete the suffix .default or .production from the initial configuration file for the Meta Service to apply the configurations defined in it.

About parameter values

If a parameter is not set in the configuration file, Nebula Graph uses the default value. Not all parameters are predefined. And the predefined parameters in the two initial configuration files are different. This topic uses the parameters in nebula-metad.conf.default.

For all parameters and their current values, see Configurations.

Basics configurations

Name Predefined value Description
daemonize true When set to true, the process is a daemon process.
pid_file pids/nebula-metad.pid The file that records the process ID.
timezone_name - Specifies the Nebula Graph time zone. This parameter is not predefined in the initial configuration files. You can manually set it if you need it. The system default value is UTC+00:00:00. For the format of the parameter value, see Specifying the Time Zone with TZ. For example, --timezone_name=UTC+08:00 represents the GMT+8 time zone.
local_config true When set to true, the process gets configurations from the configuration files.
minimum_reserved_bytes - Specifies the minimum remaining space of each data storage path. When the value is lower than this standard, the cluster metadata operation may fail. This configuration is measured in bytes. The default value is 1073741824, namely, 1GB.

Note

  • While inserting property values of time types, Nebula Graph transforms time types (except TIMESTAMP) to the corresponding UTC according to the time zone specified by timezone_name. The time-type values returned by nGQL queries are all UTC time.
  • timezone_name is only used to transform the data stored in Nebula Graph. Other time-related data of the Nebula Graph processes still uses the default time zone of the host, such as the log printing time.

Logging configurations

Name Predefined value Description
log_dir logs The directory that stores the Meta Service log. It is recommended to put logs on a different hard disk from the data.
minloglevel 0 Specifies the minimum level of the log. That is, no logs below this level will be printed. Optional values are 0 (INFO), 1 (WARNING), 2 (ERROR), 3 (FATAL). It is recommended to set it to 0 during debugging and 1 in a production environment. If it is set to 4, Nebula Graph will not print any logs.
v 0 Specifies the detailed level of the log. The larger the value, the more detailed the log is. Optional values are 0, 1, 2, 3.
logbufsecs 0 Specifies the maximum time to buffer the logs. If there is a timeout, it will output the buffered log to the log file. 0 means real-time output. This configuration is measured in seconds.
redirect_stdout true When set to true, the process redirects thestdout and stderr to separate output files.
stdout_log_file metad-stdout.log Specifies the filename for the stdout log.
stderr_log_file metad-stderr.log Specifies the filename for the stderr log.
stderrthreshold 2 Specifies the minloglevel to be copied to the stderr log.

Networking configurations

Name Predefined value Description
meta_server_addrs 127.0.0.1:9559 Specifies the IP addresses and ports of all Meta Services. Multiple addresses are separated with commas.
local_ip 127.0.0.1 Specifies the local IP for the Meta Service. The local IP address is used to identify the nebula-metad process. If it is a distributed cluster or requires remote access, modify it to the corresponding address.
port 9559 Specifies RPC daemon listening port of the Meta service. The external port for the Meta Service is predefined to 9559. The internal port is predefined to port + 1, i.e., 9560. Nebula Graph uses the internal port for multi-replica interactions.
ws_ip 0.0.0.0 Specifies the IP address for the HTTP service.
ws_http_port 19559 Specifies the port for the HTTP service.
ws_h2_port 19560 Specifies the port for the HTTP2 service.
ws_storage_http_port 19779 Specifies the Storage service listening port used by the HTTP protocol. It must be consistent with the ws_http_port in the Storage service configuration file.
heartbeat_interval_secs 10 Specifies the default heartbeat interval. Make sure the heartbeat_interval_secs values for all services are the same, otherwise Nebula Graph CANNOT work normally. This configuration is measured in seconds.

Caution

The real IP address must be used in the configuration file. Otherwise, 127.0.0.1/0.0.0.0 cannot be parsed correctly in some cases.

Storage configurations

Name Predefined Value Description
data_path data/meta The storage path for Meta data.

Misc configurations

Name Predefined Value Description
default_parts_num 100 Specifies the default partition number when creating a new graph space.
default_replica_factor 1 Specifies the default replica number when creating a new graph space.

RocksDB options configurations

Name Predefined Value Description
rocksdb_wal_sync true Enables or disables RocksDB WAL synchronization. Available values are true (enable) and false (disable).
Last update: September 23, 2021
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