[From MySQL Developer Zone
It's no secret that corporations are swimming in more data than ever before. IDC has recently pegged data growth at 48% a year, which means that corporate data nearly doubles every two years at many companies. In addition, purchased applications and custom built systems continue to bring in new databases that require attention, and business intelligence remains a red-hot area for modern enterprises with many companies building analytic data warehouses or data marts that continually feed information to key decision makers.
A serious challenge for today's database professional is linking together the many "data islands" that exist in a data center as many databases tend to be siloed on separate servers, which makes it hard to correlate data that is related but marooned on many different physical server islands. This can especially be true of MySQL servers as its tremendous ease-of-use can actually cause data island problems before a DBA knows it. This problem can surface if they have lots of MySQL servers running that have separate but related data that occasionally must be used together as one logical database.
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