> RocksDB and HNSW were sharded across 200 cores, 4 TB of RAM, and 82 TB of SSDs.

Was your experience with ivfpq not good? I’ve seen big recall drops compared to hnsw, but wow, takes some hardware to scale.

Also did you try sparse embeddings like SPLADE? I have no idea how they scale at this size, but seems like a good balance between keyword and semantic searches.