Mishards — Distributed Vector Search in Milvus

Introduces Mishards, a distributed solution for Milvus enabling horizontal scaling for massive datasets (10B+ vectors). Details the Mishards architecture including service discovery (ZooKeeper, etcd, Consul), load balancing (Nginx, HAProxy), Mishards nodes (stateless, scalable), write-only Milvus nodes (single, HA required), read-only Milvus nodes (stateful, scalable), shared storage, and metadata service (MySQL). Explains how Mishards breaks down requests, routes them to read-only nodes, and merges results. Discusses read-only node scalability through sharding and horizontal scaling. Highlights the integration with OpenTracing for service invocation tracing and Prometheus/Grafana for monitoring.