What is the reason for the low CDN hit rate?

The reason for a low CDN (Content Delivery Network) hit rate typically involves several factors:

1. Geographical Distribution: If the content is not distributed effectively across different geographical locations, users far from the origin server may experience higher latency and lower hit rates.

   Example: A user in Asia accessing a website hosted in North America might experience slower load times because the content is not cached at edge servers close to them.

2. Cache Invalidation: Frequent updates to content can lead to cache invalidation, causing the CDN to fetch fresh content from the origin server more often instead of serving it from the cache.

   Example: A news website that constantly updates its articles will have a lower hit rate because each new article requires the CDN to retrieve it from the origin.

3. Improper Cache Configuration: Misconfigured cache settings can lead to either too short or too long cache durations, affecting how often content is refreshed from the origin.

   Example: Setting a very short cache time for static assets like images will result in the CDN frequently checking the origin for updates, reducing the hit rate.

4. High Origin Server Load: If the origin server is under heavy load, it might respond slower to CDN requests, leading to lower hit rates.

   Example: During a sale event, an e-commerce site might experience high traffic, causing the origin server to respond slowly and reducing the effectiveness of the CDN.

5. Network Issues: Network congestion or interruptions between the origin server and the CDN can lead to lower hit rates.

   Example: A network outage between the data center and the CDN edge servers can prevent content from being cached effectively.

To improve CDN hit rates, consider optimizing content distribution, configuring cache settings appropriately, reducing origin server load, and ensuring reliable network connectivity. For instance, services like Tencent Cloud offer robust CDN solutions with features like intelligent routing and automated cache management to help improve hit rates and overall performance.