These numbers line up nicely with what I've experienced on much smaller scales (I've never personally cared about more than a few hundred spinning drives at once), which is that in a nice mix of old, middle-aged, and new drives, 5-10% go kaput each year.
Incidentally, about "consumer-grade drives", the last time I looked into this, I was led to believe that if it's SATA and 7200RPM (or less), there's no hardware distinction. It's just firmware. Consumer drives try very hard to recover data from a bad sector, while Enterprise/RAID drives have a recovery time limit to prevent them being unnecessarily dropped from an array (which will have its own recovery mechanisms). That's it.
Well Intel tells us different story[1] that promises
1. More performance
2. Less vibration (improves performance)
3. ECC Memory
There is a long feature reference that mentions things like: higher RPM, more quality, larger magnets, air turbulance control, dual processors, etc.
I'm not a spec in hard drives, just that I remember reading this stuff when trying to figure out do I need it. In the end, For my small-scale corporate file server, I chose zfs raidz with consumer grade disk drives.
A marketing team at Intel tells us a vague story about what is either a very vague or very specific set of drives, or may be about an entirely hypothetical set of drives. It's not clear.
They even admit to the problem themselves at the end:
"Some hard drive manufactures may differentiate enterprise from desktop drives by not testing certain enterprise-class features, validate the drives with different test criteria, or disable enterprise-class features on a desktop class hard drives so they can market and price them accordingly. Other manufacturers have different architectures and designs for the two drive classes. It can be difficult to get detailed information and specifications on different drive modes."
That PDF tells me nothing interesting. It's marketing crap for clueless executives, not a technical analysis. (Given their absurd obsession with "Higher RPM" as some sort of defining characteristic, it's not even relevant to the statement I made in the first place.)
Incidentally, about "consumer-grade drives", the last time I looked into this, I was led to believe that if it's SATA and 7200RPM (or less), there's no hardware distinction. It's just firmware. Consumer drives try very hard to recover data from a bad sector, while Enterprise/RAID drives have a recovery time limit to prevent them being unnecessarily dropped from an array (which will have its own recovery mechanisms). That's it.