# Multiple Sitemaps on a single Domain
> Markdown version of https://brajeshwar.com/2008/maintain-multiple-sitemaps-on-a-single-domain/ — 2008-02-28
Do you have more than one website, or rather lots of them? You can now reduce one hassle of the many that goes in maintaining lots of websites, blogs -- the ability to place Sitemaps for multiple hosts on a single host through robots.txt.
We know how to include auto-discovery of Sitemaps using robots.txt. Google have announced a new way for Sitemap cross-submissions using Google Webmaster Tools, making it possible to submit Sitemaps for multiple hosts on a single dedicated host.
For instance, if I want to submit and maintain Sitemaps for each of these sites --
- www.domain.com
- sub-domain.domain.com, and
- blog.domain.com
and to make things easier, I want to host all the Sitemaps on `domain.com`.
I can make the best out of cross-submission support by telling the search engines (Google, Yahoo!, Microsoft) where the Sitemaps are with robots.txt --
- The robots.txt for domain.com would include: `Sitemap: http://www.domain.com/sitemap-www-domain.xml`
- Similarly, the robots.txt for sub-domain.domain.com would include: `Sitemap: http://www.domain.com/sitemap-sub-domain.domain.xml`
- And for the third one, the robots.txt for blog.oinam.com would include: `Sitemap: http://www.domain.com/sitemap-blog-domain.xml`
Here are a few other useful notes about the implementation
- robots.txt can have multiple "Sitemap:" references.
- Limit the size of robots.txt file to less than 1 MB.
- If multiple sitemaps for a domain include the same URL with conflicting metadata (i.e. priority, change frequency, etc), the metadata will be disregarded and just the URL will be considered.
- Individual sitemap files should never be larger than 10 MB when uncompressed. This includes all sitemap file formats: XML, RSS and Text.