--- title: Web farm synchronization mechanisms --- > 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). When you make changes to content on a server, the system logs the changes into the database as **web farm tasks**. The server then notifies other servers in the web farm, which retrieve the web farm task data from the database and make appropriate changes in their file system or memory. The system provides two ways to notify servers about changes in the web farm. ## URL notifications Every Kentico instance contains a page that web farm servers can send requests to when generating web farm tasks. The other web farm servers don't get involved in the process until they are notified about the changes. When this happens, each server fetches its tasks and processes them accordingly. This is the default behavior in instances not running on Microsoft Azure. ## Database notifications With database notifications, a column in the _CMS\_WebFarmServer_ database table is used. The column contains a time stamp, which indicates the time of the last change made on a server. On the application side, a routine runs in a separate thread which continuously polls the database to find out whether a time stamp changed. To enable this mechanism, add the following key to your web.config file. You don't need this key if your application runs on Microsoft Azure, as this mechanism is used on Azure by default. ```csharp ```