# Storage and Lifecycle

> How Agent Stream persists data, manages process execution lifecycles, hot-reloads configuration changes, and coordinates active-passive failover.

Restarting a production appliance to apply a routine configuration change, or losing in-flight requests during that restart, is disruptive to live traffic. Agent Stream manages entity persistence, process lifecycles, and configuration updates through hot-reloading in-memory state and persisted storage backends. [Trust Fabric integration →](/products/affinidi-trust-fabric/agent-stream/concepts/trust-fabric-integration.md)

## Appliance Instance

An Appliance Instance is a running Agent Stream process or deployment. Distinct from a stored Gateway record, an Appliance Instance is what serves live traffic; a Gateway record is the stored representation of an appliance in the Fabric. See [Trust Fabric integration →](/products/affinidi-trust-fabric/agent-stream/concepts/trust-fabric-integration.md).

## Storage Backend

The Storage Backend is the persistence boundary for an entity kind. Agent Stream persists to local JSON storage by default, with optional encryption at rest using AES-256-GCM or AWS KMS envelopes.

## What Hot Reload lets you change without a restart

Hot Reload is the ability to pick up supported configuration changes without restarting the appliance. Almost all configuration, such as policies, budgets, guardrails, and provider settings, is hot-reloadable and takes effect without a restart or dropped in-flight requests.

## What still requires a restart to change

Startup-Only Configuration is consulted only at process boot; changing it requires a restart rather than a hot reload. Listener bindings, TLS certificates, DynamoDB table names for failover, and the identity hash pepper are typical startup-only settings.

## How Warm-Standby Failover keeps exactly one leader serving traffic

Warm-Standby Failover is an active-passive replica pattern where two appliances share a DynamoDB conditional lease so exactly one leader serves traffic, while a standby reloads shared time-series snapshots on promotion. Connection-point listeners reserve a generation before connecting; demotion fences stale tasks so they cannot re-register.

## Related

- [Architecture](/products/affinidi-trust-fabric/agent-stream/concepts/architecture.md): Overview of data plane and control plane architecture.

- [Trust Fabric integration](/products/affinidi-trust-fabric/agent-stream/concepts/trust-fabric-integration.md): Appliance-to-appliance DIDComm connectivity and gateway records.

- [Security and access control](/products/affinidi-trust-fabric/agent-stream/concepts/security-and-access-control.md): Identity hash peppers, secrets, and security controls.