If an Akamai edge server has cached an url, will it share that content with other edge servers, or will edge servers that don't have the content cached locally go back to the origin to get the content?
I'd love to have an official, Akamai document detailing this process, but will of course appreciate any input!
Note that I have tried this out, and see what I expect is the answer - that edge servers will go back to origin at least some of the time to get the content, even if it resides on another edge server.
For example, I left a curl running all weekend to request a resource that caches for 7 days, and see that I got 3 different cached responses (different by response headers), and can see that the origin must've been accessed at least 3 times,
$ cat /t/akamai_dump_requests_all_weekend.txt | grep x-rate-limit-reset| sort | uniq -c
259 < x-rate-limit-reset: 1489776484
1 < x-rate-limit-reset: 1489779291
12 < x-rate-limit-reset: 1489781137
and I see alot of different edge servers listed in my dumps as well: