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While this loads — worth knowing
ElastiCache RedisnotElastiCache Memcached
Redis has data structures — sorted sets, counters, pub/sub. Memcached has plain keys and nothing else.
Loading…
While this loads — worth knowing
Redis has data structures — sorted sets, counters, pub/sub. Memcached has plain keys and nothing else.
Architecture pattern
when users on several continents need the app to feel local
A full stack in each region and DNS sending people to the nearest healthy one. The edge absorbs the static and cacheable traffic; the regional stack handles what has to be computed near the user.
In the order a request or a record moves through it. Each one links to the page that explains it.
Phrases that, when you meet them in a scenario, mean this shape rather than another. They are the tell, and they are what an exam question is built around.
Replicating writes across regions is the hard part, and multi-region consistency is where these designs usually break.
Every shape has one. A design decision with no stated downside is usually a decision nobody has finished making.
These run through some of the same services, which is exactly why a brief that fits one can look like it fits another.
Reading a shape and producing one from a scenario that never names a service are different skills, and the exam asks for the second. The scenarios give you the brief; you draw the architecture and it is scored against what the brief requires.