Azure Content Delivery Network (CDN) is designed to send audio, video, applications, images, and other files faster and more reliably to customers using servers that are closest to each user. If you want to put binary files and blobs closer to your user, then CDN can be the right solution.
The CDN caches publicly available objects at strategically placed locations to provide maximum bandwidth for delivering content to users.
Essentially, when a user wants some content, the first user gets the data from the source server. When you use a CDN, that data is then cached at a site near the user. So subsequent users can get the data from the cache instead of going all the way back to the source server. For example, if a picture stored in a blob is in a European data center in Azure, a user in Portland Oregon would be able to access the file from a server set up in Seattle, making your image load much faster.
Azure Redis Cache helps your application become more responsive even as user load increases and leverages the low latency, high-throughput capabilities of the Redis engine. This separate distributed cache layer allows your data tier to scale independently for more efficient use of compute resources in your application layer.
Redis is an open source, BSD licensed, advanced key-value cache and store. It is often referred to as a data structure server since keys can contain strings, hashes, lists, sets, sorted sets, bitmaps and hyperloglogs. Redis supports a set of atomic operations on these data types.
Microsoft Azure Redis Cache is based on this cache and store. It gives you access to a secure, dedicated Redis cache, managed by Microsoft, providing the best of both worlds: the rich features and ecosystem of Redis, and reliable hosting and monitoring by Microsoft.
You can use Redis from most programming languages used today.
Azure Redis Cache leverages Redis authentication and also supports SSL connections to Redis.
The purpose of this article is to help you decide if Azure Redis is the right technology for your project. The Azure documentation is pretty good to help you get started, but is spread all over the place, so this article focuses on the steps to get started, and gives you a peek into what your code looks like. (If you are like me, you can often tell if the technology is a good fit by seeing code.)
NOTE: Of course, you can use Redis without Azure. For more information on that, see Distributed Caching using Redis Server with .NET/C# Client.