> For the complete documentation index, see [llms.txt](https://docs.natsclub.cn/cn/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.natsclub.cn/cn/yi-chan/stan/changes/configuring/persistence.md). # Persistence By default, the NATS Streaming Server stores its state in memory, which means that if the streaming server is stopped, all state is lost. On server restart, since no connection information is recovered, running applications will stop receiving messages and new published messages will be rejected with an `invalid publish request` error. Client libraries that support and set the `Connection Lost` handler (refer to [this](https://github.com/nats-io/stan.go#connection-status) for more information) will be notified that the connection is lost with the error `client has been replaced or is no longer registered`.\ Still, this level of persistence allows applications to stop and later resume the stream of messages, and protect against applications disconnect (network or applications crash). * [File Store](/cn/yi-chan/stan/changes/configuring/persistence/file_store.md) * [SQL Store](/cn/yi-chan/stan/changes/configuring/persistence/sql_store.md) --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.natsclub.cn/cn/yi-chan/stan/changes/configuring/persistence.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.