Service Outage Protection

When Guaranteed Messaging is enabled, the following features can be used to protect against disruptions to messaging service should a router or an entire data center go out of service:

Appliance Redundancy

High-availability (HA) appliance redundancy is a feature that allows two Solace appliances to be configured as a redundant pair. When two appliances are configured as an HA pair, if one of the appliances in the pair is taken out of service or fails, its mate automatically takes over responsibility for the clients associated with the unavailable appliance.

Router redundancy is supported for Solace appliances that have installed ADBs and HBAs. It also requires a customer-supplied external disk storage array. For more information, refer to Appliance Redundancy and Fault Tolerance.


The Replication facility provides a data center redundancy and disaster recovery solution for the Solace Message platform. It uses corresponding Message VPNs at separate Replication sites to ensure that Guaranteed Messaging clients can continue to have service through one of the Replicated Message VPNs should one data center become unavailable.

If a service switch-over to one Replication site occurs, clients can reconnect to the same Message VPN at a different Replication site to continue to obtain service, and any messages that were received, but not consumed, before the service interruption can be delivered to them.

For more information, refer to Data Center Replication.


Config-Sync is a configuration synchronization feature that is used for:

  • HA redundant pairs—Config-Sync should be enabled for both routers in an HA pair to automatically synchronize initial configuration information and subsequent changes between both redundant Solace routers. When Config‑Sync is enabled for both routers in a HA pair, it can also increase the speed at which Guaranteed Messaging information is handled if a redundancy switchover occurs.
  • Replicated Message VPNs—Config-Sync must enabled on all routers in each Replication site to automatically synchronize configuration parameters between Replication‑enabled Message VPNs of the same names that exist on separate Replication sites.