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Milvus Server Configuration

Configuration overview

The configurations apply to both single server Milvus and all nodes of a distributed Milvus cluster.

Milvus file structure

After you have successfully started Milvus server, you can see a Milvus file under the path home/$USER/milvus, which contains the following child files:

  • milvus/db (database storage)
  • milvus/logs (log storage)
  • milvus/conf (configuration file folder)

    • server_config.yaml (server configuration)
    • log_config.conf (log configuration)

Updating configurations

Editing the configuration file

You can directly edit the configuration file. You must restart Milvus every time a configuration file is updated.

$ docker restart <container id>

Updating configurations during runtime

You can use Milvus clients to update parameters in server_config.yaml. Refer to Client Reference for more information.

When you use Milvus clients to update the following parameters, the updates take effect immediately.

  • section cache_config

    • cpu_cache_capacity
    • cache_insert_data
  • section engine_config

    • use_blas_threshold
    • gpu_search_threshold
  • section gpu_resource_config

    • enable
    • cache_capacity
    • search_resources
    • build_index_resources

For other parameters, you still need to restart Milvus for the changes to take effect.

server_config.yaml parameters

Before changing these settings, welcome to consult Milvus team on GitHub issues or our Slack channel.

Section server_config

Parameter Description Type Default
address IP address that Milvus server monitors. String 0.0.0.0
port Port that Milvus server monitors. Port range: (1024, 65535). Integer 19530
deploy_mode Milvus deployment type. Options are single, cluster_readonly and cluster_writable. DeployMode single
time_zone Use the UTC-x or UTC+x to specify a time zone. For example, use UTC+8 for China Standard Time. Timezone UTC+8
web_port Port that Milvus web server monitors. Port range: (1024, 65535). You can use the Milvus web server to communicate with the Milvus RESTful API. Integer 19121

Section db_config

Parameter Description Type Default
backend_url URL for metadata storage. Use SQLite (for single server Milvus) or MySQL (for distributed cluster) to store the metadata.
The format of backend_url is: dialect://username:password@host:port/database. (dialect can be either mysql or sqlite, depending on which database you use.
String sqlite://:@:/
preload_collection Determines how to preload collections into memory after Milvus server restarts. Collections can be selected for fully or partially preloading.
To preload all the existing collections, use '*' (quote included); To preload some collections, list the specific collection names, separated by comma. If you choose not to preload any collection, keep it empty ( ).
StringList
auto_flush_interval The interval, in seconds, at which Milvus automatically flushes inserted data in the cache to disk. If auto_flush_interval is 0, automatic flushing at a fixed interval is disabled. However, when the cache is full, Milvus always flushes data to disk, regardless of the value of auto_flush_interval. Integer 1 (s)

Section storage_config

Parameter Description Type Default
primary_path Primary directory used for the vector data files, index files, and the metadata. Path /var/lib/milvus
secondary_path A semicolon-separated list of secondary directories used vector data files and index files. Set this parameter when the data size is too much to fit in the primary_path.
Each file, whether in primary_path or secondary_path, is assigned an equal part of the imported data. Data Size per Directory = Total Data Size / Number of Directories. So make sure the available storage space in these files are enough.
Path

Section metric_config

Parameter Description Type Default
enable_monitor Set to true to enable the monitoring function. Boolean false
address IP address of the Pushgateway. IP 127.0.0.1
port Port of the Pushgateway. Integer 9091

Section cache_config

Parameter Description Type Default
cpu_cache_capacity The size of the CPU memory for caching data for faster query. The sum of cpu_cache_capacity and insert_buffer_size must < the total CPU memory size. Integer 4 (GB)
insert_buffer_size Maximum memory size used by the buffer for data insertion. The sum of insert_buffer_size and cpu_cache_capacity must < the total memory. Integer 1 (GB)
cache_insert_data If set to true , the inserted data will be loaded into the cache immediately for hot query. Boolean false

Section engine_config

Parameter Description Type Default
use_blas_threshold A Milvus performance tuning parameter. The threshold value must be compared with nq to decide whether the usage of OpenBLAS library will be triggered.
If nq >= use_blas_threshold , OpenBLAS will be used. The search response times do not fluctuate, but the search speed is relatively slow.
If nq < use_blas_threshold , AVX or SSE will be used. The search speed will be enhanced, however with slight fluctuation of search response times. The value should be >= 0.
Integer 1100
gpu_search_threshold A Milvus performance tuning parameter. The threshold value must be compared with nq to decide if the search computation will be executed on GPUs only.
If nq >= gpu_search_threshold , the search computation will be executed on GPUs only.
If nq < gpu_search_threshold , the search computation will be executed on both CPUs and GPUs.
Integer 1000

Section gpu_resource_config

This section determines whether to enable GPU support/usage in Milvus. GPU support, which uses both CPU and GPUs for optimized resource utilization, can achieve accelerated search performance on very large datasets.

To switch to CPU-only mode, just set enable to false.

Parameter Description Type Default
enable Whether to enable GPU usage in Milvus. Boolean true
cache_capacity Size of the GPU memory for caching data for faster query. The size must be less than the total GPU memory size. Integer 1 (GB)
search_resources GPU devices used for search computation in Milvus. Must be in format: gpux, where x is the GPU number, such as gpu0. You can use multiple GPUs for search computation. DeviceList gpu0
build_index_resources GPU devices used for index building in Milvus. Must be in format: gpux, where x is the GPU number, such as gpu0. You can use multiple GPUs for search computation. DeviceList gpu0

Note: In Milvus, index building and search computation are separate processes, which can be executed on cpu, gpu, or both. You can assign multiple GPUs to index building and search computation by adding GPUs under search_resources or build_index_resources. The following YAML code shows an example:

  search_resources:
    - gpu0
    - gpu1
  build_index_resources:
    - gpu0
    - gpu1

Section tracing_config

Parameter Description Type Default
json_config_path Absolute path for tracing config file. Milvus creates a no-op tracer if the value is empty. Path

Section wal_config

Parameter Description Type Default
enable Whether to enable write-ahead logging (WAL) in Milvus. If WAL is enabled, Milvus writes all data changes to log files in advance before implementing data changes. WAL ensures the atomicity and durability for Milvus operations. Boolean true
recovery_error_ignore Whether to ignore logs with errors that happens during WAL recovery. If true, when Milvus restarts for recovery and there are errors in WAL log files, log files with errors are ignored. If false, Milvus fails to restart when there are errors in WAL log files. Boolean true
buffer_size Sum total of the read buffer and the write buffer in MBs. buffer_size must be in range [64, 4096] (MB) . If the value you specified is out of range, Milvus automatically uses the boundary value closest to the specified value. It is recommended you set buffer_size to a value greater than the inserted data size of a single insert operation for better performance. Integer 256 (MB)
wal_path Location of WAL log files. String
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