Certainly anything is possible if you're a large enough (or strategic enough) customer, but I tend to doubt that Dropbox had a year or two head start on these m

Certainly anything is possible if you're a large enough (or strategic enough) customer, but I tend to doubt that Dropbox had a year or two head start on these models. For one thing, I wouldn't build out my entire storage system with one model from one vendor that hasn't been field proven yet. With 4T drives, you can easily achieve raw storage of 2.9PB in a rack. The previous top of the line (10T drives) yield 7.4PB in a rack. 14T pushes that up to 10.4PB. Higher densities are possible as well. The most I'm aware of is 90x 3.5" in 4U; available from Supermicro, Dell and others. The depth of the chassis can be problematic, and the way Supermicro designed it isn't super great in my opinion. Sacrificing hot swap capability could potentially yield higher density (~100-ish drives), which I think is a reasonable tradeoff if you're deploying a ton of these hosts and you can let dead drives hang out for a while. I'm not aware of anyone who makes a chassis like that that can be bought off the shelf though. At these drive sizes though, I would be leery of having that much storage attached to a single host from a fault domain perspective. I think the next step is either a highly dense 2U chassis (HP has something like this, but only 28 bays) or a two server 4U chassis (Dell has something like this).