Overview
This section covers deploying Stalwart in a clustered environment, with guidance on cluster size, topology options, and storage backend recommendations for distributed setups.
Sizing
A common question when planning a Stalwart deployment is how many nodes are required. The answer depends on expected user load, availability requirements, and performance targets. The clustering architecture is designed to start small and scale horizontally as demand grows.
Storage
In a clustered Stalwart deployment, the choice of storage backends affects reliability, scalability, and performance. Mail systems combine structured metadata, large binary objects, and transient data, so Stalwart separates storage into four backend singletons:
Topology
In a Stalwart cluster, administrators control how user-facing services are distributed across nodes. This is distinct from node roles, which assign background maintenance tasks such as store maintenance or certificate renewal. Cluster topology focuses on which protocols (IMAP, JMAP, WebDAV, SMTP) each node serves.