Dovecot Clustered Configuration vs. External Storage Replication for Zero-Downtime Migration

Dovecot Clustered Configuration vs. External Storage Replication for Zero-Downtime Migration

The objective is to migrate a small Dovecot deployment to a new node configuration while preserving continuous service availability for existing mail clients.

Key constraints involve determining whether Dovecot's hot reload mechanism can synchronize module settings across all cluster members without service interruption, and whether the underlying external storage replication guarantees that active sessions and mailbox state remain consistent during the transition.

How does hot reload behavior affect configuration synchronization across clustered nodes during migration? Can external storage replication ensure uninterrupted session state when reconfiguring Dovecot clusters?