How much data does the entire Youtube library require?

"As per Youtube stats, 1 hour of video is being uploaded every second, so 2.4 GB of video is uploaded every second.

* 86400 seconds/day = 207.36 TB / day
* 365 days/year = 75.686 PB / year

"...Approximately 76 PB of video data is stored in Youtube every year. At the time of writing, 2 TB hard drives cost approximately $100 or less.

"So 76 PB x $50 / TB = $3,784,320 on storage costs
= $3.8 million in storage costs

"So there we go. Approximately $4 million in storage costs per year

"Amazon’s Cloudfront CDN charges $0.12 per GB for low-end customers. I suspect that Google/Youtube, through their combination of in-POP networks, working with ISPs, etc, is able to keep that cost down. Let’s say $0.01 per GB.

So $0.015 per GB = $15 per TB = $15,000 per PB = $15M per EB
Cost = 6 EB * $15M / PB = $90,000,000
= $90 million

"So there we go. Approximately $90 million a year in networking costs. (Again, this number could vary wildly..."

https://sumanrs.wordpress.com/2012/04/14/youtube-yearly-costs-for-storagenetworking-estimate/