Using Google's App Engine as CDN for static files

The app engine is a cloud computing platform and is not designed to be a CDN. While your data may be stored on multiple nodes those nodes are not edge-cache nodes so they will not offer the same benefits that a CDN would. You can compare GAE vs various CDNs using the CloudHarmony.com speed test. Here were the results when I tested today:

Order   Service Location    Type    Size    Time (secs) Rate (Mb/s)
1   Google AppEngine    download    1.00 MB     3.50    2.29
2   Google AppEngine    upload      512.00 KB   3.57    1.12
3   Google AppEngine    website     102.55 KB   0.75    1.07

Order   Service     Type        Size    Time (secs) Rate (Mb/s)
05  EdgeCast CDN    download    1.00 MB 1.03    7.77
02  Cotendo CDN     download    1.00 MB 1.08    7.37
12  Amz CloudFront  download    1.00 MB 1.11    7.19
10  CacheFly CDN    download    1.00 MB 1.29    6.19
08  Azure CDN       download    1.00 MB 1.36    5.90
07  Internap CDN    download    1.00 MB 1.47    5.43
09  VoxCAST CDN     download    1.00 MB 1.55    5.17
04  SimpleCDN       download    1.00 MB 1.65    4.84
06  MaxCDN          download    1.00 MB 1.69    4.73
03  Highwinds CDN   download    1.00 MB 1.81    4.43
11  Akamai CDN      download    1.00 MB 2.22    3.60
01  LimeLight CDN   download    1.00 MB 2.34    3.42

You'll see that the CDN ends up being 2-7 times faster than GAE for file downloads.

MaxCDN (1TB for $10 - $0.01/GB) and Akamai (1TB for $100 - $0.10/GB - via reseller VPS.net) are the best priced CDNs we've found. MaxCDN is based on Anycast which performs very well for smaller files (i.e. webpage images, CSS, etc.) due to generally lower latency, while Akamai does better with larger files due to significantly more POPs.