Acquia recommends the following best practices for using Acquia Edge:

• Caching recommendations for Acquia Edge
  • Updating cached content before expiration
  • Cache tags on Acquia Edge
• Logs and log sharing

Caching recommendations for Acquia Edge

Acquia recommends the following defaults for page caching rules in Edge CDN:

• Edge Cache TTL (Time To Live): 1 minute
• Browser Cache TTL: set to Respect Existing Headers

You should also configure Page Cache Maximum Age (the amount of time Varnish® and Drupal take to cache your assets) to your desired value—typically 30 minutes to one day. Edge CDN will contact Varnish once per minute for updated copies of an asset.

For more information on caching with Acquia Edge, see Caching recommendations for Acquia Edge.

Updating cached content before expiration

If your content or assets change at origin in your Drupal website, and you must update the cached copies of the assets before the Page Cache Maximum Age expiration date, Acquia recommends you use the Acquia Purge module.

After you configure the Acquia Purge module, content updates will purge selected portions of Varnish cache. The next time Edge CDN requests the asset from Varnish, Edge CDN will receive the newly-updated content.

Cache tags on Acquia Edge

When purging caches on Edge CDN using the API or the dashboard, the Cache-Tag Header (including whitespace and commas) must not exceed 255 bytes in total length after the header field name. If the supplied Cache-Tag header exceeds 255 bytes in length, Acquia Edge will purge only the tags in the first 255 bytes.

Logs and log sharing

Acquia Edge provides subscribers with access to web log data on a per-domain basis. You can forward the web logs for aggregation and analysis using Enterprise Log Sharing.

Acquia Edge retains audit logs for 18 months and access logs for three days. You may access the logs using the Cloudflare API.

Best Practices for Acquia Edge