[teraflop]

On top of that, it seems to encourage an extremely wasteful and expensive use of resources. The blog post claims that it "costs just a few dollars per month, and in theory scales near infinitely" but as soon as you start scaling, the cost is going to grow a lot.

As an example, take the use of S3 as a "cache" for the most recent messages in each channel. Suppose you're hosting a decent-sized collection of chat rooms, handling a total of 100 messages/second. The PUT requests alone would run you over $1000/month, even though the same amount of traffic could be easily served by a single small EC2 instance for a few percent of the cost.

[vidarh]

S3 alone is expensive enough that it often pays to rent managed servers or instances elsewhere to act as a frontend cache for any external access to the files if you for whatever reason "must" use S3 (durability would be a good justification - getting that right is hard; getting it to the point where you trust it to be right is even harder)

E.g. 1TB worth of retrievals from S3 can buy me a dedicated server with 16TB of disk space and 30TB of inclusive traffic. Doesn't take a very big cache hit ratio before caching all external reads becomes profitable.

If cost is a consideration, it's pretty rare for AWS to be the way to go for anything but batch processing where you need instances or short periods of time in the first place.