If their system could not handle more than 2 billion records then there is no point failing over to a backup system which would probably also have the same limitation.

Seems more likely to me that the id of their tracking record table was a 32 bit signed integer which maxes out at 2,147,483,647 and when they say they "increased its data storage capacity" they just changed it to a larger data type.

Thanks, and now I wonder if people realize this article is dated from one year ago... "06 May 2008".