[zmmmmm]

This is what I've never understood about GAE.

If you're small, GAE is free, but then, you could host anywhere for peanuts - just buy a linode or a small EC2 instance, it doesn't really matter.

Once your site becomes big, cost is going to matter and GAE is as expensive as anyone else, last time I looked, quite a bit more expensive.

So there is really not much advantage, it is only free when it doesn't matter, and when it does you're going to start looking for the exit pretty quickly, not just because of cost but because GAE imposes all kinds of limits which may make dealing with your problems much much harder.

[grandalf]

I'm curious how the billing breaks down for your app. Is it mostly CPU quota? Or bandwidth? etc.

[zmmmmm]

For me it's CPU and bandwidth (it's lots of real-time image transformations). So if you look at GAE it's just about the same as EC2 (0.10 / hr for CPU, 0.10/0.12 GB for data, 0.15/GB for storage), but there is no "reserved instances" discount which is really significant (unless I'm unaware of it). On balance it's comparable to EC2 but you have way less flexibility.

[mike_esspe]

1) It's hard to move without rewriting the code. 2) It's hard to get a consistent data snapshot without taking your service off for several hours.