Re: Why would these be bad for general purpose arrays?
A "mere" 25% - 50% capacity increase???
MERE ? ? ?
ARE YOU KIDDING ? ? ?
Have you read the stats on helium drives? They're something like 45% more energy efficient per unit of storage (per TB). They run cooler, requiring less air conditioning/heat removal, which creates a second tier of energy savings. At 6TB per drive, they require less rack space. And they're NOT going to have SMR's pathetic rewrite speeds.
A drive with those characteristics is a logistical and economic bonanza for the big storage customers.
Shingle is niche. I personally will not knowingly buy a shingled drive. I see it as fundamentally flawed with built-in counter-measures that amount to a handicap. Not so helium.
Assuming that WD/HGST can get 6 to 8 years out of their helium drives -- at which point they will be amusingly small and obsolete -- the helium innovation will be a total winner. It's simple and requires virtually no compromises in drive performance. The helium idea is one that will probably spread down to the consumer level and will most likely be around for the remainder of spinning storage.
I'll also bet that it won't be too long before Seagate has it's own helium drives.
Helium will improve any and every type of spinning drive -- including SMR and HAMR drives. Think about that.
My money is on the "H" technologies: Helium and HAMR.
Biting the hand that feeds IT
