Proper Dual Server

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1

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I just want to make sure I understand how to setup dual email servers
I run rocky linux
current stalwart version
enterprise licence
foundations db
use s2 amazon compatible storage for emails et

So, I would install the above on my second server
connect to the same?? s2 compatible bucket that currently holds emails, or make a new one?

change dns to mail1.sitename.com and mail2.sitename.com

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on

2

This surfaces a much better answer: this is about clustering, not two independent servers.

For proper dual-server (clustered) setup with Stalwart, both nodes should connect to the same shared storage backends, not separate ones. Any node in a Stalwart cluster can serve any protocol independently as long as it points at shared storage: same FoundationDB deployment, same S3-compatible bucket for blobs, and the same search/in-memory stores if configured. You don’t create a second bucket, both instances share the one that already holds your mail.

Specific things to set up:

  1. Storage: Install Stalwart on the second Rocky Linux host and configure it to use the identical Data Store (FoundationDB) and Blob Store (your S3-compatible bucket) settings as the existing node. See Storage.

  2. Coordination: With two nodes, the default peer-to-peer coordination mode is sufficient (no external coordinator required), though Kafka/NATS/Redis are options for larger deployments. See Cluster overview.

  3. Hostname: Each node needs a unique OS hostname (used only to acquire a node-id lease). But the client-facing identity (SMTP banner, TLS cert, protocol responses) should be the same across both nodes, set via defaultHostname on the SystemSettings singleton, e.g. mail.sitename.com, not separate mail1/mail2 identities. See Load balancing.

  4. DNS: Rather than pointing clients at mail1 and mail2 separately, the recommended pattern is to publish MX/service records for a single public name (mail.sitename.com) that resolves to both nodes (round-robin) or sits behind a load balancer, so failover between the two is automatic and transparent to clients. See DNS records and Load balancing.

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