# NatsOptions.NumReplicas

[Type overview](/orleans/docs/api/csharp/microsoft.orleans.streaming.nats/orleans.streaming.nats.natsoptions/) | [Properties](/orleans/docs/api/csharp/microsoft.orleans.streaming.nats/orleans.streaming.nats.natsoptions/properties/)

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.Streaming.NATS/NatsOptions.cs)

```csharp
public int NumReplicas
```

The number of stream replicas in the NATS JetStream cluster. Higher values improve availability during node restarts (R3 survives single-node failures in a 3-node cluster). The NATS server enforces that the value is odd and does not exceed the cluster size. Defaults to 1. Set to 3 for production clusters with ≥ 3 nodes.