Progress Sonic 8.5 Installation and Upgrade Guide - Product ...

Chapter 1: Overview of Installations and Upgrades
Clusters and replicated brokers are advanced groupings of brokers that are designed
specifically to ensure continuity and scalability.
4. Cluster of Brokers (Node C) — All the member brokers of a cluster can be running
as each broker is upgraded. The cluster tolerates other cluster members that continue
to run in the prior version, as each one in turn is upgraded. The cluster node never
stops.
5. Replicated Brokers (Node D) — When broker replication is functioning, one peer is
in the ACTIVE mode while the other is in STANDBY mode. The upgrade of the primary
peer completes by restarting its upgraded version, forcing failover to the peer, and
then resumption of replication between the peers. Then, when the upgrade of the other
peer is performed, the upgrade of the node is complete.
Throughout the upgrade process, the node was always available. Fault-tolerant clients
handle transitions between the peers, keeping session and transaction states intact.
6. Cluster of Replicated Brokers (Node E) — Combining the benefits of clusters and
replicated brokers provides the most resilient and scalable node structure. Implicitly,
architects of such topologies want zero-downtime. And they can achieve it.
The Zero-Downtime Upgrade feature takes enterprise resilience to a new level, one where
staying up to date on product releases, and striving for 100% non-stop processing can both
be optimized in service level agreements.
46 Progress Sonic Installation and Upgrade Guide 8.5