As one of the biggest private companies and employers in the world, Wal-Mart Stores Inc. has to contend with an enormous amount of legal actions every year. For many, just keeping up with the variety of cases, which run the gamut from tort actions to class action law suits, can be formidable.

But for Aaron Crews, who for three years served as senior associate general counsel and global head of e-discovery at Wal-Mart, the core challenge often comes down to one hurdle: effectively managing and understanding ever-growing relevant data sources.