Any hard data on lifespan of NOS drives?
Not that I'm aware of.
Where do you have electrolytic caps in them?
Potentially in the same kinds of areas where motherboards would have them, i.e. for power smoothing. There's a good chance they switched to all solid electrolyte before then, but I am not certain of this.
Lubricants, am I wrong to think that if it runs fine for the first week-month, it's cleared the hurdle?
I don't think you can assume that. Sub-standard lubrication will show up as accelerated wear, but a month of running may not be enough to tell you whether that's the case.
Corrosion, well, the best I can do is hope hardware warehouses aren't drafty shacks by the sea.
Anywhere with high humidity could be an issue if the warehouse isn't climate-controlled. Even a sealed bag will allow some diffusion through the plastic, and eventually the little pack of silica gel gets saturated and stops soaking up water vapor.
Official acoustics specs are the same for Ultrastar 7K4000
, HC310 (7K6)
, though no idea what's reality. I've seen complaints about HGST in general.
Yes, historically HGST drives have not been known for being quiet. Some models also tended to make unusual (for a hard drive) noises on occasion, but this was "normal".
One advantage for the older models is error rate. For 4TB, the newer HC310 is with 1E14
, the 7K6000 and 7K4000 with 1E15
I don't think you can assume that the drive still meets factory error rate specs 5 years on. All it really tells you is that WHEN THE DRIVE WAS NEW, it should've been of higher quality than current consumer drives.
All of the above said, none of it should be a huge issue unless the drive has been stored under sub-optimal conditions or otherwise mis-handled. My main concern would be if you DO have a problem, is the warranty still valid? If you're thinking of buying several of them, I suppose you could test this by buying one at first, and checking the warranty status via HGST's web site.