Cloudfront content download speed is too slow.

Question

Cloudfront was deployed using Origin on the ALB connected to the web server.
Using Managed Policy, static files are subject to the CachingDisabled policy, and dynamic files are subject to the CachingOptimized and AllViewer policies.

Content download speed is too slow in the browser regardless of the cache policy in place. It doesn't matter for small files, but for large images, fonts, etc., the download time may exceed 1 minute.

This problem does not exist when attached directly to EC2 or LB.

I need help solving what the problem is.

Pandurangaswamy · Answer

Hi  jh,

Follow the below steps you can take to troubleshoot the issue:

1. **Check CloudFront Logs:** Enable logging in CloudFront and check the logs to see if there are any errors or delays reported during file downloads.

2. **Review Cache Policies:** Double-check the cache policies applied to your CloudFront distribution. Ensure that the caching configurations for static and dynamic files are correctly set up.

3. **Origin Response Time:** Check the response time from your ALB when CloudFront requests files. Slow response times from the ALB could contribute to overall download delays.

4. **Compression Settings:** Ensure that compression settings are optimized both at the ALB level and within CloudFront. Compressing files can help reduce download times, especially for larger assets.

5. **Origin Shield:** Consider implementing an Origin Shield to reduce the load on your ALB and improve response times for CloudFront requests.

6. **Network Latency:** Investigate potential network latency issues between CloudFront and your ALB. This could involve reviewing network configurations and routing.

7.**Resource Optimization:** Optimize your web server configuration, including settings related to TCP connection handling, keep-alive timeouts, and maximum concurrent connections.

MikeLim · Answer

> Using Managed Policy, static files are subject to the CachingDisabled policy, and dynamic files are subject to the CachingOptimized and AllViewer policies.

Can you share the AWS Region your ALB is in? 
If you are using Origin Shield, make sure you use nearest Region.  Else disable it.

Also, should the caching be reversed? 
i.e.

* Static files : CachingOptimized
* Dynamic files: CachingDisabled

Edit: You are in ap-northeast-2 Seoul Region. Do ensure you select the correct Price class. There are 3
1. Use all edge locations (best performance)
2. Use only North America and Europe
3. Use North America, Europe, Asia, Middle East, and Africa

Item 2  (North America and Europe) is not appropriate for your use case

Also check if CloudFront is caching your static content. You may have to browse your web site a few timees. To verify,  use web browser developer tools. Go to network, select a static content, and check Headers, Response (screenshot below).

![Enter image description here](/media/postImages/original/IMHGBcHHREQOesufqgMEWL0g)

A `X-Cache` value of `Hit from cloudfront` indicates caching.
The X-Amz-Cf-Pop value is indicative of your POP location. Korea is likely ICN*

Cloudfront content download speed is too slow.

Relevant content