I have started preparing for the OCMJEA and am reading the SCEA Study Guide.
While reading through the section "Impact of Dimensions on Service Level Requirements" in the second chapter, I came across something that I don't quite agree with.
In the Modularity subsection it says that Modularity can actually decrease availability. I could not really think of an example where modularity can decrease availability.
I am working on a modular system, where each module is loosly coupled to other modules. So Module A can depend on Modules B,C and D. if for eg. Module B is not available,(is down), the system as a whole is still available and can handle requests for Modules C and D via A.
This, IMO atleast increases availability of the system to the end user.
Can someone please explain if my interpretation is correct or not and if there are situations where Modularity can actually decrease availability.
High availability is connected into action to separate your solution into independent pieces that can be run on separate nodes. Imagine a solution that was not properly modulated and therefore can not be set to run separately. This is the case of running your solution as Multi-Tier Architecture - http://docs.oracle.com/cd/E13222_01/wls/docs81/cluster/planning.html Regards.