The following article tells that the "default" Redis server configuration in Azure has 16 Redis databases: https://msdn.microsoft.com/en-us/library/azure/cbe6d113-7bdc-4664-a59d-ff0df6f4e214#RedisConfig.
It also states that:
Any values that are configurable, such as max-memory-policy, are configurable through the portal.
As for me I've not found such setting in Azure Portal.
Is it possible to change amount of Azure Redis databases?