how can I create a cluster between two Informix?
I think you may want to "shadow" an Informix server, right?
If so, you can search Informix Information Center, for your specific Informix version, about HDR feature.
There are also several tutorials published in DeveloperWorks, about configuring and managing HDR clusters.
If you need specific additional help, ask in www.iiug.org forums, we are always there.