Magento already has a built-in Google sitemap generator. Nevertheless, there is one problem – it is generating a single file which includes all the category, product and CMS page links. But, due to the Google specifications it should not contain more than 50 000 items. So, if your shop is large enough, then your XML sitemap file will be quite big and will cause the error from the crawlers site. That is why, we decided to write an article that describes the extension which generates a sitemap with the index file and numerous sub-files for each type of the pages (products, categories, CMS).