Sitemap Index
In one sentence
A file listing other sitemap files, used when a site exceeds the limits of a single one.
Analogy Mental model
The master catalogue with a volume for each floor. Social sciences here, literature there, science at the back.
In practice What you actually do
One index pointing at per-section files keeps each child under fifty thousand URLs and fifty megabytes, and makes regeneration cheap because a publish only touches its own section.
Where people get burned Pitfalls
An index referencing a sitemap that returns errors poisons the set. Validate the children before the parent, and keep the index referenced in robots.txt so the crawler finds the hierarchy.
This entry was written in English from the Chinese original, not machine-translated. Read the Chinese version →