IBM has recently released a new RedBook, called "Informix Dynamic Server 11: Extending Availability and Replication"

It looks to be a comprehensive review, covering:

Preparing the technical infrastructure
High availability data replication
HDR: Advanced use scenarios
Remote Standalone Secondary servers
Shared Disk Secondary servers
Updatable Secondary servers
Connection management in an IDS cluster environment
Enterprise Replication
Instantiating Enterprise Replication
Making changes in Enterprise Replication
Monitoring and troubleshooting ER
Coexistence of HA technologies
Managing clusters with the Open Admin Tool
Setting up replication on a single machine
Embedding an IDS cluster in an OS driven HA solution

The appendices have some especially fascinating and useful stuff in them. (And MACH11 is just the coolest stuff we've done in ages! ;-)