With the latest Azure update, Microsoft gave some love to the Redis Cache implementation. One of the things that got added is the Redis Cache Advisor.
On your Azure Redis Cache instance, you’ll find a new Recommendations blade.
This blade is empty in normal situations but if any special condition occurs, like high memory usage, high server load, etc… an alert is displayed on the Redis Cache blade and the Recommendations blade will be filled with extra information on how to fix this(most of the time buy a bigger box 
More information: https://azure.microsoft.com/en-us/documentation/articles/cache-configure/#redis-cache-advisor