> ## Documentation Index
> Fetch the complete documentation index at: https://gcore-doc-1894.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Optimize large file delivery
Large File Delivery Optimization is designed for CDN resources that serve files larger than 10 MB. When enabled, Gcore CDN requests content from the origin in 10 MB chunks using HTTP range requests, caches each chunk independently, and assembles the response from the cached portions.
A range request includes the `Range` HTTP header to indicate the byte or part of the content to be returned. If the request has a `Range: bytes=123537047-123545047` header, the CDN requests a 10 MB chunk from the origin (byte range 115343360-125829119), caches this chunk, and serves the requested range (123537047-123545047) to the end user.
For this option to work, the origin server must support range requests.
## Configuration guidelines
Large File Delivery Optimization can be configured in the Resource Settings and Rules. Review the following requirements and recommendations before configuring the option:
* The origin server must support HTTP Range Requests.
* The `Content-Length` and `Etag` headers must be consistent across the origin.
* When enabled, the option applies to all content in the CDN resource, which can increase the load on the origin. Consider activating [Origin Shielding](/cdn/cdn-resource-options/general/enable-and-configure-origin-shielding) before enabling this feature, or enable it during off-peak hours.
* Remember to [purge the cache](/cdn/clear-cdn-resource-cache-by-url-pattern-or-all) after enabling Large File Delivery Optimization.
* Large File Delivery Optimization cannot be used in conjunction with [Fetch Compressed](/cdn/cdn-resource-options/compression/configure-fetch-compression), [Gzip Compression](/cdn/cdn-resource-options/compression/configure-gzip-and-brotli-compression#gzip), and [Brotli Compression](/cdn/cdn-resource-options/compression/configure-gzip-and-brotli-compression#brotli) within the Resource Settings or within the same rule.
* Large File Delivery Optimization is generally unnecessary for HLS and MPEG-DASH because these formats already split media into small segments that are cached independently.
## Configuration steps
To enable Large File Delivery Optimization via the Gcore Customer Portal:
1. In the [Gcore Customer Portal](https://portal.gcore.com), navigate to **CDN** > **CDN resources**.
2. Click the CNAME of the required CDN resource to open **Resource settings**.
3. Navigate to the **OPTIONS** tab.
4. In the left menu, click **Content** to scroll to the Content section.
5. Enable the **Large files delivery optimization** toggle.
6. Click **Save changes**.
When Large files delivery optimization is enabled, the HTTP `Etag` header is concealed in responses.