Storage Service configurations¶
NebulaGraph provides two initial configuration files for the Storage Service, nebula-storaged.conf.default and nebula-storaged.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_configtofalse. If modified, the NebulaGraph 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, NebulaGraph 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 parameters that are not included in nebula-metad.conf.default, see nebula-storaged.conf.production.
Note
The configurations of the Raft Listener and the Storage service are different. For details, see Deploy Raft listener.
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-storaged.pid |
The file that records the process ID. |
timezone_name |
- | Specifies the NebulaGraph time zone. This parameter is not predefined in the initial configuration files. 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. |
Note
- While inserting property values of time types, NebulaGraph 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. timezone_nameis only used to transform the data stored in NebulaGraph. Other time-related data of the NebulaGraph 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, NebulaGraph 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 |
graphd-stdout.log |
Specifies the filename for the stdout log. |
stderr_log_file |
graphd-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 Storage Service. The local IP address is used to identify the nebula-storaged process. If it is a distributed cluster or requires remote access, modify it to the corresponding address. |
port |
9779 |
Specifies RPC daemon listening port of the Storage service. The external port for the Meta Service is predefined to 9779. The internal port is predefined to 9777, 9778, and 9780. 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 |
19779 |
Specifies the port for the HTTP service. |
ws_h2_port |
19780 |
Specifies the port for the HTTP2 service. |
heartbeat_interval_secs |
10 |
Specifies the default heartbeat interval. Make sure the heartbeat_interval_secs values for all services are the same, otherwise NebulaGraph 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.
Raft configurations¶
| Name | Predefined value | Description |
|---|---|---|
raft_heartbeat_interval_secs |
30 |
Specifies the time to expire the Raft election. The configuration is measured in seconds. |
raft_rpc_timeout_ms |
500 |
Specifies the time to expire the Raft RPC. The configuration is measured in milliseconds. |
wal_ttl |
14400 |
Specifies the lifetime of the RAFT WAL. The configuration is measured in seconds. |
Disk configurations¶
| Name | Predefined value | Description |
|---|---|---|
data_path |
data/storage |
Specifies the data storage path. Multiple paths are separated with commas. One RocksDB example corresponds to one path. |
minimum_reserved_bytes |
268435456 |
Specifies the minimum remaining space of each data storage path. When the value is lower than this standard, the cluster data writing may fail. This configuration is measured in bytes. The default value is 1073741824, namely, 1GB. |
rocksdb_batch_size |
4096 |
Specifies the block cache for a batch operation. The configuration is measured in bytes. |
rocksdb_block_cache |
4 |
Specifies the block cache for BlockBasedTable. The configuration is measured in megabytes. |
engine_type |
rocksdb |
Specifies the engine type. |
rocksdb_compression |
lz4 |
Specifies the compression algorithm for RocksDB. Optional values are no, snappy, lz4, lz4hc, zlib, bzip2, and zstd. |
rocksdb_compression_per_level |
\ | Specifies the compression algorithm for each level. |
enable_rocksdb_statistics |
false |
When set to false, RocksDB statistics is disabled. |
rocksdb_stats_level |
kExceptHistogramOrTimers |
Specifies the stats level for RocksDB. Optional values are kExceptHistogramOrTimers, kExceptTimers, kExceptDetailedTimers, kExceptTimeForMutex, and kAll. |
enable_rocksdb_prefix_filtering |
true |
When set to true, the prefix bloom filter for RocksDB is enabled. Enabling prefix bloom filter makes the graph traversal faster but occupies more memory. |
enable_rocksdb_whole_key_filtering |
false |
When set to true, the whole key bloom filter for RocksDB is enabled. |
rocksdb_filtering_prefix_length |
12 |
Specifies the prefix length for each key. Optional values are 12 and 16. The configuration is measured in bytes. |
enable_partitioned_index_filter |
- | When set to true, it reduces the amount of memory used by the bloom filter. But in some random-seek situations, it may reduce the read performance. |
misc configurations¶
Caution
The configuration snapshot in the following table is different from the snapshot in NebulaGraph. The snapshot here refers to the stock data on the leader when synchronizing Raft.
| Name | Predefined value | Description |
|---|---|---|
snapshot_part_rate_limit |
8388608 |
The rate limit when the Raft leader synchronizes the stock data with other members of the Raft group. Unit: bytes/s. |
snapshot_batch_size |
1048576 |
The amount of data sent in each batch when the Raft leader synchronizes the stock data with other members of the Raft group. Unit: bytes. |
rebuild_index_part_rate_limit |
4194304 |
The rate limit when the Raft leader synchronizes the index data rate with other members of the Raft group during the index rebuilding process. Unit: bytes/s. |
rebuild_index_batch_size |
1048576 |
The amount of data sent in each batch when the Raft leader synchronizes the index data with other members of the Raft group during the index rebuilding process. Unit: bytes. |
RocksDB options¶
| Name | Predefined value | Description |
|---|---|---|
rocksdb_db_options |
{} |
Specifies the RocksDB database options. |
rocksdb_column_family_options |
{"write_buffer_size":"67108864","max_write_buffer_number":"4","max_bytes_for_level_base":"268435456"} |
Specifies the RocksDB column family options. |
rocksdb_block_based_table_options |
{"block_size":"8192"} |
Specifies the RocksDB block based table options. |
The format of the RocksDB option is {"<option_name>":"<option_value>"}. Multiple options are separated with commas.
Supported options of rocksdb_db_options and rocksdb_column_family_options are listed as follows.
rocksdb_db_optionsmax_total_wal_size delete_obsolete_files_period_micros max_background_jobs stats_dump_period_sec compaction_readahead_size writable_file_max_buffer_size bytes_per_sync wal_bytes_per_sync delayed_write_rate avoid_flush_during_shutdown max_open_files stats_persist_period_sec stats_history_buffer_size strict_bytes_per_sync enable_rocksdb_prefix_filtering enable_rocksdb_whole_key_filtering rocksdb_filtering_prefix_length num_compaction_threads rate_limit
rocksdb_column_family_optionswrite_buffer_size max_write_buffer_number level0_file_num_compaction_trigger level0_slowdown_writes_trigger level0_stop_writes_trigger target_file_size_base target_file_size_multiplier max_bytes_for_level_base max_bytes_for_level_multiplier disable_auto_compactions
For more information, see RocksDB official documentation.
For super-Large vertices¶
When the query starting from each vertex gets an edge, truncate it directly to avoid too many neighboring edges on the super-large vertex, because a single query occupies too much hard disk and memory. Or you can truncate a certain number of edges specified in the Max_edge_returned_per_vertex parameter. Excess edges will not be returned. This parameter applies to all spaces.
| Property name | Default value | Description |
|---|---|---|
| max_edge_returned_per_vertex | 2147483647 | Specifies the maximum number of edges returned for each dense vertex. Excess edges are truncated and not returned. This parameter is not predefined in the configuration files. |
Compatibility
The reservoir sampling algorithm in NebulaGraph 1.x is no longer supported in NebulaGraph 2.6.2.
Storage configurations for large dataset¶
When you have a large dataset (in the RocksDB directory) and your memory is tight, we suggest that you set the enable_partitioned_index_filter parameter to true. The performance is affected because RocksDB indexes are cached.