Does NATS persist state?

[Ann-Geo]

Hi,
I had a question about persistent state and server restarts.
We have been running a 5 server NATS jetstream cluster for more than 20 days. We tried to stop one of the servers in the cluster.
At this time, we used the NATS CLI tool to retrieve the stream info/report, however the cluster gave an error showing: 'Jetstream service temporarily unavailable'. This happened even if there were other 4 four other servers (quorum) up and running in the cluster. All our streams are configured to use in-memory storage.

Following this we tried to restart the stopped server in the cluster. Even after performing the server restart, we could not retrieve the stream report for any of the streams.

So is it possible that NATS servers are persisting state somewhere in the filesystem? And this state is required for successful server restarts?
Our NATS server version is 2.10.14.

[wallyqs]

Hi, yes the nats-servers with JetStream require stable storage and if using Kubernetes need to make sure to use these charts: https://github.com/nats-io/k8s