Service Outage Protection

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

• Redundancy
• Replication
• Config-Sync

Redundancy

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

Event broker redundancy is supported for PubSub+ appliances that have ADBs and HBAs installed. It also requires a customer supplied external disk storage array.

For more information about appliance HA support, refer to High Availability for Appliances, and for information about HA support on software event brokers, refer to High Availability for Software Event Brokers.

Replication

The Replication facility provides a data center redundancy and disaster recovery (DR) solution for PubSub+ event brokers. 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 for Disaster Recovery.

Config-Sync

Configuration synchronization, or Config-Sync, is used for:

• HA redundant pairs

  Config-Sync should be enabled for both event brokers in an HA pair to automatically synchronize initial configuration information and subsequent changes between both redundant event brokers. When Config‑Sync is enabled for both event brokers 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 be enabled on all event brokers in each Replication site to automatically synchronize configuration parameters between Replication‑enabled Message VPNs of the same names that exist on separate Replication sites.

For more information, refer to Config-Sync.