It allows for the caching of static content and assets, which are served globally on AWS and close to the user.   This helps improve SEO (search engine optimization), reduced load times and optimization of your website's overall user experience.

DoIT Web Hosting will provide account contacts the CDN information, in order to integrate it with the W3 Total Cache (W3TC) plugin.

Please contact us at: webhosting@doit.wisc.edu if you have a publicly accessible WordPress site and would like to proceed with a CDN and W3 Total cache.

Tips for using W3TotalCache plugin

• If you feel stuck in the UI and settings remember the breadcrumbs menu and also the "General Settings" page to bring you back to the main jumping off page. 
• All changes to any settings need to be saved with the "Save Settings" button in the top right corner of the settings page in order to take effect

W3TotalCache General CDN Configuration

• Click "Performance" either on the top or in the left navigation
• Select "General Settings" from the left navigation or the top right nav under "Settings"
• Scroll down to the CDN section
• Under the "CDN Type" drop down, select "Amazon Cloudfront over S3" under the "Origin Push" section
• In the upper right hand corner, click the blue button "Save Settings"

W3TotalCache Advanced CDN Configuration

Advanced config is located on the WordPress side bar under Performance -> CDN -> Advanced section

• Enter Access key ID
• Enter Secret key
• Enter Bucket name (example full name: dwh-edu.wisc.doit.webhosting.wwwtest.cdn as AWS adds the ".s3.us-east-2.amazon.aws.com" to the end)
• Set bucket to Ohio region (or whichever region you originally created the S3 bucket)
• Ensure "Set objects to publicly accessible on upload" is set to "Disabled (don't apply an ACL)"

Plugin issues & things to consider

• If the site is using a child theme, you will need to explicitly include the child theme files in the CDN upload. Scroll down to the Advanced section, and inside of "Custom file list" add this so that the parent uw-theme gets uploaded, as the plugin doesn't seem to be aware of how child themes work: {wp_content_dir}/themes/uw-theme/*
• If the WordPress site updates plugins and WordPress automatically, you may want to check "Export changed files automatically" This should prevent the scenario where a plugin/WordPress automatically updates and the cache does not. 

Update the CDN Cache

At the start, Empty all Caches. However...

Generally speaking, do not clear all caches. You want to be as surgical as you can - prove with an incognito or in private browsing window that something should have changed, and the "wrong" or "old" file is cached.

Upload buttons to click:

• Host wp-includes/files
• Host theme files
• Custom files

Temporarily disable the CDN

There isn't really an on/off button if you want to disable the CDN. You could always disable the plugin but a simpler way is to navigate to "General settings -> CDN" and uncheck enable.