Ace the Alibaba Cloud Certification 2025: Power Up with the ACA Developer Quiz!

Implementing ApsaraDB for Redis in Cluster Mode is the best choice for maintaining maximum uptime when caching content in front of an RDS (Relational Database Service). Cluster Mode allows for data distribution across multiple nodes and provides enhanced availability and fault tolerance. In the event of a node failure, the system can automatically redirect requests to other functioning nodes in the cluster, thereby ensuring that the caching service remains operational and responsive to requests without significant downtime.

In contrast, deploying ApsaraDB for Redis in Standalone Mode limits the availability to a single instance, which can create a single point of failure. If that instance goes down, all cached data would be temporarily inaccessible, resulting in downtime.

Using a local caching solution may provide faster access to data but requires management of the caching layer within the application infrastructure, which could complicate the setup and might not offer the same levels of redundancy.

A CDN (Content Delivery Network) helps distribute content closer to users but is typically focused on static content and may not be ideal for caching dynamic content specific to an RDS instance. While it can enhance performance for publicly accessible web content, it does not directly contribute to caching from an RDS standpoint with the goal of maximum uptime.

Therefore, Cluster Mode for A