Here's an unpopular answer - don't store 10PB of data. Find a way for your startup to work without needlessly having to store insane amounts of data that will likely never be needed.
This is like an ISP asking how they can get hooked up to the internet.
Apple didn't start manufacturing with mega Foxconn contracts. They had to figure that out along the way as their scale demanded.
However I share your sentiment: doing things the same way but cheaper is usually not the solution. Doing things differently (in-sourcing) might be the path forward.
Apple created something people wanted and sold at a price that would still make money if it was assembled by hand. They didn't form a company around a commodity like data storage.
Data storage is a commodity. Everyone already has some, online storage companies already exist. If you don't know how to store a lot of data and your company's whole purpose is to store a lot of data, it sounds like something that should have been worked out before making the company.
Maybe I’m wrong though. Perhaps the real secret sauce is the end user experience and the kind of storage you use on the backend doesn’t matter at all.
However I bet that the “cloud storage space” is pretty crowded and lots of people shop on price more than anything. If your business model is all about price, then finding economical storage is critical to your company and needs to be part of your core competency.
If price isn’t that important, perhaps it doesn’t matter... the “winners” would win no matter how expensive their storage solution is.
But honestly.... I feel like part of your core competency needs to be managing the storage system.
It's a bit different nowadays that a lot of scaling tech is commoditized, but still means things like negotiating new contracts, finding & fixing the odd pieces that weren't stressed before, etc.
(congrats on hitting the new usage levels + good luck! we're at a much smaller scale, but trying to figure out some similar questions for stuff like web-scale publishing of data journalism without dying on egress $, so it's an interesting thread...)
We are a photo/video storage service.
Sticking points I see are, 1. If you get it wrong you'll need some form of UX that keeps the users from getting to angry about it. 2. The cost of moving the data between hot/cold storage might make this prohibitive until a much larger scale. 3. User behaviors might not be predictable enough.
Because there may be an inflection point that offering monetary compensation for data loss, rather than actually trying to store the data, would make more financial sense. I.e., "All data > than 2 years gets silently expunged, and anyone trying to retrieve it at that point gets $10 per gig in compensation for 'our mistake'".
Please don't actually consider that though.
(And if you don't already, I would also consider making it so items that are in the trash for some period of time, say 30 days, get deleted automatically as well, possibly with a reminder email a few days before)
(And lastly, depending on user profiles and usage, incentives around reducing resolution/quality of photos and video, and automating that in the app as part of the sync process, might provide some opportunities to reduce costs of storage > the lost revenue of cheaper plans.)
"We use ML to ensure we only store the highest quality data, freeing you from the chains of having too much worthless data and nothing to do with it."