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Re:135 Terabytes for $12,000 by wazoox on Wednesday October 12, 2011 @03:08AM (#3101832)
Actually the difference is only in firmware; each drive is tested when reaching the end of the factory line, and the test results decide if it'll be desktop or enterprise. So physically the only difference is the label.

Different brands makes the separation more or less clear : WD desktop drives firmwares are explicitly crippled to be made almost unusable in RAID arrays (on the web and forums you'll find countless horror stories of lost arrays); Seagate and Hitachi desktop drives work about OK in RAID arrays, but you may have surprises at times.

So what's the difference? First, the desktop drive assumes to be alone. In case of a read or write error, it will try and retry to access the data for several long minutes (long timeout). Pro drives assume to be in RAID arrays, in case of an error they fail almost immediately not to block any outstanding IOs to the array.

Another difference is in vibration compensation. Desktop drive don't use their movement detectors to compensate from drive-induced chassis vibration, which in case of high IO will significantly reduce throughput by augmenting error rate.

Re:135 Terabytes for $12,000 by bradfa on Wednesday October 12, 2011 @08:10AM (#3102588)
If you (or someone you know) has a write up detailing these statements and tests showing them to be true, I'd be very interested in reading more about this. Please do share.

It sounds like what you're saying makes sense, from a drive business and manufacturing perspective.

Re:135 Terabytes for $12,000 by wazoox on Wednesday October 12, 2011 @10:02AM (#3102955)
> If you (or someone you know) has a write up detailing these statements and tests showing them to be true, I'd be very interested in reading more about this. Please do share.

This is NDA information :) I'm repeating what I've heard from drive makers and my experience after setting up several thousands of RAID systems. I didn't made tests recently, but vibrations can kill an array performance. I've seen a chassis where the central drive slot (among 24) wasn't usable because it vibrated more than the others :)