Hey pc ... gonna make me think on a Sunday afternoon :) 2 years in Dell's enterprise support, I obviously saw more than the average administrator would see ... I would guess maybe 8-10 times.  Of those, I'd say most (but not all) had verified faulty drives - I do remember two distinct times that drives passed full diagnostics (there may have been a few more).  In the 4 years since, I have seen a puncture 2 times on servers I've worked with - both had verified faulty drives. Total, I would "guess" no more than 20-25% of punctures occurred for reasons other than bad drives. Given the ease of diagnosing a puncture on a PERC vs. a SAS 5/6 (with the controller log), I'm not sure how many of the '8-10' above were verified or unverified punctures, or how many might be missing from those numbers having occurred on those lower-end controllers. You?  
Flash... Curious, how many times have you run into punctured arrays, either with or without physical errors...approximately how many with or without physical errors? Thanks   
TheFlash1932 Punctures