about Node roles in milvus

[hxlsky]

In milvus,there are Proxy node,Query node,Index node,Data node,What roles are they respectively?

[yhmo]

Typically a milvus cluster contains these components: https://milvus.io/docs/main_components.md

Responsibility for each component:

• Pulsar/Kafka acts as a message queue to store WAL(write-ahead-log) for insert/delete requests, and time-tick messages for data consistency. All the inserted data will be stored in Pulsar/Kafka before being consumed by datanode/querynode.
• MinIO/S3 is the major data storage of Milvus, all the original data and index data are stored here. The data is organized as collection/partition/segment/field. Data is stored as column-based.
• Etcd stores the system metadata of Milvus, including schema of collections, runtime address of each component, paths of data/index of each segment, etc.
• Proxy receives requests from clients and dispatches requests to other components.
• Query node loads segments into memory for search, including growing segments and sealed segments.
• Data node persists data into segments, and merges small segments into large segments.
• Index node builds indexes for sealed segments.
• Root coordinator maintains data consistency and the entire system state. Milvus manages data consistency by time-tick machinery: https://milvus.io/docs/time_sync.md#Time-Synchronization.
• Data coordinator manages data nodes, and assigns tasks to data nodes.
• Query coordinator manages query nodes and index nodes(in old versions, index coordinator manages index nodes, in new version, index coordinator is removed)