IBM Cloud applications are not designed with database replication capability for distributed sites. The closest approach to this would be separate instances (each in a different data center) with friend relationships for cross-project instance linking. As for performance, the system itself performs equally well in any data center. The issue is network latency and, most importantly, bandwidth. Although latency is certainly affected by distance, it is also affected by the number of network hops. Bandwidth is an issue on the IBM end; bandwidth is always constrained by your enterprise network. Another option is to set up multiple site-to-site VPNs to get the traffic onto the SoftLayer backbone.
Additionally, you can use WAN accelerators or proxy cache server options. Both of those require deployment on your network, and you can request infrastructure support and guidance. All these options incur additional cost. Before IBM can explore any setup option, you must provide details of your user population locations, and you probably conduct tests and collect data to identify the most likely problem spots and the best solution.
Scalability of applications and data hosted in the IBM Cloud environment
IBM Cloud architecture is built to support both vertical and horizontal scaling. In other words, IBM Cloud has the ability to add additional hardware resources such as disk storage, memory, and CPU, and to extend an application with additional servers.