Pre-load assets on an Azure CDN endpoint

Important

This feature is available only with Azure CDN Standard from Verizon and Azure CDN Premium from Verizon products. It is not supported on Azure CDN from Akamai. For a comparison of CDN features, see Azure CDN product features.

By default, assets are cached only when they're requested. Because the edge servers have not yet cached the content and need to forward the request to the origin server, the first request from each region can take longer than subsequent requests. To avoid this first-hit latency, pre-load your assets. In addition to providing a better customer experience, pre-loading your cached assets can reduce network traffic on the origin server.

Note

Pre-loading assets is useful for large events or content that becomes simultaneously available to many users, such as a new movie release or a software update.

This tutorial walks you through pre-loading cached content on all Azure CDN edge nodes.

To pre-load assets

  1. In the Azure portal, browse to the CDN profile containing the endpoint you wish to pre-load. The profile pane opens.

  2. Click the endpoint in the list. The endpoint pane opens.

  3. From the CDN endpoint pane, select Load.

    CDN endpoint pane

    The Load pane opens.

    CDN load pane

  4. For Content path, enter the full path of each asset you wish to load (for example, /pictures/kitten.png).

    Tip

    After you start entering text, more Content path text boxes will appear to allow you to build a list of multiple assets. To delete assets from the list, select the ellipsis (...) button, then select Delete.

    Each content path must be a relative URL that fits the following regular expressions:

    • Load a single file path: ^(?:\/[a-zA-Z0-9-_.%=\u0020]+)+$
    • Load a single file with query string: ^(?:\?[-_a-zA-Z0-9\/%:;=!,.\+'&\u0020]*)?$

    Because each asset must have its own path, there's no wildcard functionality for pre-loading assets.

    Load button

  5. When you are finished entering content paths, select Load.

Note

There's a limit of 10 load requests per minute per CDN profile and 50 concurrent paths can be processed at one time. Each path has a path-length limit of 1024 characters.

See also