Relative advantages of storage using Amazon Web Services S3 vs Google Application Engine

Question

What do you see as the advantages and disadvantages of Amazon Web Services S3 compared with Google Application Engine? The cost per gigabyte for the two is, at the time I ask,

Answer 1

GAE has a limit of 10MB each on static files uploaded through appcfg.py (look right at the bottom of http://code.google.com/appengine/docs/python/tools/uploadinganapp.html). Obviously you can write code to slice large files into bits and reassemble at download time, but it suggests to me that Google doesn't expect App Engine to be used just as a simple CDN, and that if you want to use it as one you'll have to do some work. S3 does the job out of the box, all you have to do is grab a third-party interface app.

If you want to do something non-standard with file access on S3, then probably Amazon expects you to spring for a server instance on EC2. Once this is done, you have much more flexibility than GAE's environment, but you pay more (in cash and probably in maintenance).

The plus point for GAE is that it has "cheap" on its side for small apps (up to 1GB storage, 1GB bandwidth and 1.3 million hits a day are free: http://code.google.com/appengine/docs/quotas.html). Depending on your use, this might be significant, or it might be irrelevant on the scale of your total bandwidth costs.

Coincidentally, I have just this last couple of days looked at GAE for the first time. I took an old Perl CGI script and turned it into a GAE app, which is up and running. About 10 hours total, including reading the GAE introductory docs and remembering how Python is supposed to work enough to write a couple of hundred lines. I'd speculate that's more effort than loading a bunch of files onto S3, but less effort than maintaining EC2 server(s). However, I haven't used Amazon.

[Edited to add: this sounds like the advantages are all with Amazon for commercial purposes. This may well be true, but then GAE is not yet mature and presumably will get better from here fairly rapidly. They only let people start paying in December or so, before that it was free-quota-only except by special arrangement with Google. While Google sometimes takes flack for its claims of "perpetual beta", I think GAE genuinely is still starting up. If your app is a good fit for the BigTable data paradigm, then it might scale better on GAE than EC2. For storage I assume that S3 is already good enough for all reasonable purposes, and Google's clever architecture gives GAE no advantages to compensate when all you're doing is serving files.]

* Except that Google has just offered me a preview of GAE's Java support.

** Just noticed that you can set up chron jobs, but they're limited by the same rules as any other request (30 second runtime, can't modify files, etc).