Last week, members of the German union for train operators/engineers were on strike and only a fraction of trains were operating. I had to go to Zurich, Switzerland, but most of the trains on my usual route were out of service. That's when I had my DB2 pureScale or DB2 Parallel Sysplex moment.
What is special about a DB2 Parallel Sysplex or DB2 pureScale configuration? It is a data sharing cluster. If one node in the cluster or a network connection goes down and is inaccessible, the other components can pick up the work. All this is usually transparent to the application. In my case I was the application and data at the same time: Try to get me to Zurich, discuss some issues in person, get back home.