Yes, Cloudflare + B2. Since they're part of the Bandwidth Alliance, traffic between Backblaze and Cloudflare is free. I also cache all files on Cloudflare with a "page rule" (they cache files up to 512MB), so the heavy lifting is done by them.
What am I hosting?
There's modified Google Camera app that unlocks Google's HDR+ on non-Google phones. It's an amateur thing for people that like to thinker with their Android phone. People were having issues downloading the files so I started hosting them (https://www.celsoazevedo.com/files/android/google-camera/). I also host other stuff which is used by people that install custom ROMs. Eventually all this got popular and now my personal domain uses this massive amount of bandwidth. Here's the weird thing: this domain is on a "pro" plan ($20) and they haven't said a thing (yet?).
This is not a business or a service. I have Adsense, but sometimes it's not enough to pay all expenses, so if an upgrade to an enterprise plan was required, I would be forced to close down the site or (with community support) move all this to one or two dedicated servers (you can get at least two 1Gbps servers on Hetzner or OVH for less than what the Business plan costs).
I really mean it when I say that I'm happy with Cloudflare. Without them this little hobby wouldn't exist. I only showed the email because jgrahamc asked for it and because it's not the first time I see someone mentioning "forced" upgrades.
Now, while "unlimited" is nice for what I do and for when you get popular overnight, not having a limit creates some insecurity. 80TB wasn't okay before, but 150TB is okay now? Was the email sent because CF was proxying/caching .jpg and .mp4 files? If so, do .zip and .apk files have different limits? We don't know if we have crossed the line if we don't know where the line is.
If Cloudflare does what you need, go for it. If you want a plan b, look into dedicated servers, after all not all content needs a CDN.
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I tried to edit my original comment, but the "edit" button is gone: the email was sent almost 2 years ago. At the time they also claimed to have unlimited traffic, but I received that email anyway. Maybe something changed between then and now?
I really appreciate you taking the time to reply. Thanks!
Yeah my original plan was to use B2 as storage and build my own caching system on Hetzner dedicated machines, as you suggested. Excess traffic was very reasonably priced at Hetzner at 1€ per TB. Since October 4, 2018 they've made traffic completely free. [1] However it's the B2 traffic pricing that was bugging me, as they charge $10 per TB.
When the Bandwidth Alliance got announced between Cloudflare & B2 to make B2 traffic free, it was like a dream come true. Especially because at the time this was announced the Cloudflare terms allowed for caching all legal files.
Unfortunately on October 26, 2018 Cloudflare changed their terms again to prohibit non-html caching. [2]
Thanks to your comments here and also jgrahamc saying that forcing to upgrade shouldn't happen anymore, I'm now a bit more optimistic again about using Cloudflare. I need to research & think some more to decide the exact plan, but even something like using Cloudflare to tunnel data from B2 to Hetzner for free sounds pretty nice.
[2] Use of the Service for the storage or caching of video (unless purchased separately as a Paid Service) or a disproportionate percentage of pictures, audio files, or other non-HTML content, is prohibited.https://www.cloudflare.com/terms/
Hetzner have Storage Boxes with free internal traffic.[1] Assuming they are enough for what you're trying to do, they might be a better solution than B2.
What am I hosting?
There's modified Google Camera app that unlocks Google's HDR+ on non-Google phones. It's an amateur thing for people that like to thinker with their Android phone. People were having issues downloading the files so I started hosting them (https://www.celsoazevedo.com/files/android/google-camera/). I also host other stuff which is used by people that install custom ROMs. Eventually all this got popular and now my personal domain uses this massive amount of bandwidth. Here's the weird thing: this domain is on a "pro" plan ($20) and they haven't said a thing (yet?).
This is not a business or a service. I have Adsense, but sometimes it's not enough to pay all expenses, so if an upgrade to an enterprise plan was required, I would be forced to close down the site or (with community support) move all this to one or two dedicated servers (you can get at least two 1Gbps servers on Hetzner or OVH for less than what the Business plan costs).
I really mean it when I say that I'm happy with Cloudflare. Without them this little hobby wouldn't exist. I only showed the email because jgrahamc asked for it and because it's not the first time I see someone mentioning "forced" upgrades.
Now, while "unlimited" is nice for what I do and for when you get popular overnight, not having a limit creates some insecurity. 80TB wasn't okay before, but 150TB is okay now? Was the email sent because CF was proxying/caching .jpg and .mp4 files? If so, do .zip and .apk files have different limits? We don't know if we have crossed the line if we don't know where the line is.
If Cloudflare does what you need, go for it. If you want a plan b, look into dedicated servers, after all not all content needs a CDN.
---
I tried to edit my original comment, but the "edit" button is gone: the email was sent almost 2 years ago. At the time they also claimed to have unlimited traffic, but I received that email anyway. Maybe something changed between then and now?