Sharding ni njia ya MongoDB ya upimaji wa mlalo (horizontal scaling) — kusambaza data katika seva nyingi (shards) ili database iweze kushughulikia datasets na throughput zaidi ya yale ambayo seva moja inaweza. Hugawanya data kwa shard key, MongoDB ikielekeza queries kwa shards sahihi.
Kwa nini sharding: kupima zaidi ya seva moja
A single server has limits (storage, RAM, write throughput). When data/load exceeds
what one server (even a powerful one) can handle, SHARDING distributes it:
→ data is split across multiple SHARDS (each a replica set)
→ each shard holds a SUBSET of the data → combined capacity scales horizontally
→ handles huge datasets and high write throughput
