This is exactly how it works. Queries based on some kind of id will always hit the same server, except when the server goes down. Sensei expects a semi-durable "data stream" for writes, which is very different from how most other databases work. Imagine a near-real time processing system though where updates go into a queue to be processes (financial transactions work like this). SenseiDB works great for indexing these types of events. Text search is a good example here - after you update your profile, it's put into a queue to be indexed. We don't want to wait for your profile to be indexed before we'll let you move onto another page.