I was talking about testing the impact against the sql server data. Most of the concerns that I've heard is that o/s defragmentation can cause damage to the database. I believe that is what this thread is about.
O/S defragmentation will do nothing to resolve fragmentation issues in a sql database from what I've read. If I have read incorrect info, I'd love to know. I just know that I've had no issues doing an o/s defrag on a drive with sql databases, but that doesn't mean that a problem might not happen. I wish I could say that, without a doubt, it would work perfect everytime, but that would be unrealistic.