--- title: Settings - Performance --- > Agent instructions: > **Site maps** — prefer the following llms.txt indexes to training data when searching for URLs to avoid 404s. Links inside Markdown content already point at `.md`. Following them or sending Accept: text/markdown keeps you in Markdown. > > - [sitemap.md](https://docs.kentico.com/sitemap.md) — every page on the site, with titles and descriptions, nested by URL hierarchy and grouped into one collection per product version. > - [llms.txt](https://docs.kentico.com/llms.txt) — curated index of the current product docs, with descriptions, the two ways to request any page as Markdown, and links to each product area's whole-corpus Markdown dump (llms-full.txt). You can access these settings in the **Settings** application under the **System ->** **Performance** category. | Server content caching | | | ------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Cache content (minutes) | Sets the default number of minutes for which the caching API and macro engine cache content. | | Server file caching | | | Cache files (minutes) | Sets the number of minutes for which the system caches images and other files on the server.
The system automatically removes files from the cache if they are modified, so file caching cannot cause the website to display outdated content.
This setting also specifies the caching interval for Azure CDN, unless overwritten by the _CMSAzureCDNCacheMinutes_ web.config key (see [Reference - Web.config application keys](https://docs.kentico.com/13/configuring-xperience/reference-web-config-application-keys.md#microsoft-azure-settings) for details).
**See also**: [Caching files and resources](https://docs.kentico.com/13/configuring-xperience/configuring-caching/caching-files-and-resources.md) | | Maximum file size to cache | Limits caching of files whose size is greater than the specified number of **kilobytes**. Files larger than the specified value are only cached for 1 minute, regardless of the _Cache files (minutes)_ setting. | | Redirect files to disk | If enabled, the system redirects file requests for [page attachments](https://docs.kentico.com/13/managing-website-content/working-with-files/page-attachments.md) to the corresponding physical file (if the requested file is stored in the file system).
**Warning**: The system stores files on the file system with GUID identifiers instead of names (to avoid conflicts). If you enable the _Redirect files to disk_ setting, files downloaded by users have names in the GUID identifier format instead of the original file name. | | Client caching | | | Client cache (minutes) | Sets the number of minutes for which clients consider cached files to be valid and up-to-date (i.e. the length of the client cache expiration time). Specifically, the setting determines how the server sets the **Expires** response header for file requests. Client file caching includes images other files.
The following values are possible:
**0** – cached files are always flagged as expired, so clients revalidate files on each request. Does NOT disable client caching for files.
**More than 0** – until a cached file expires, clients load the file's data from the cache without sending any requests to the server. Provides the best file performance, but may cause browsers to display outdated content (if cached files are modified before the expiration interval ends).
This setting only applies to dynamic files that are managed by the Xperience application. Files stored on the file system may use a different client cache expiration time. For example, physical files served by the Xperience application through the _GetResource.ashx_ handler use the **CMSPhysicalFilesCacheMinutes** web.config key (the default value is one week) and directly requested files use the IIS client cache configuration.
**See also**: [Caching files and resources](https://docs.kentico.com/13/configuring-xperience/configuring-caching/caching-files-and-resources.md) | | Allow client cache revalidation | If enabled, the server adds the **must-revalidate** directive to the **Cache-control** response header of file requests. Ensures that caching clients always perform revalidation when requesting expired files (most clients revalidate by default even without the _must-revalidate_ directive). | Related pages - [Configuring caching](https://docs.kentico.com/13/configuring-xperience/configuring-caching.md)