> For the complete documentation index, see [llms.txt](https://samypesse.gitbook.io/algolia-faq/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://samypesse.gitbook.io/algolia-faq/basics/what-is-a-cluster.md).

# What is a cluster?

A cluster is a group of servers. On all of our plans, your data is duplicated in a cluster of three identical servers.

There are multiple reasons for us to create this redundancy:

* Availability: If one or two servers go down the users of your website won’t be affected. We’ve never had 3 servers from the same cluster down at the same time.
* Redundancy: Having 3 live copies of your data makes it very unlikely that we’ll ever lose it
* Scalability: Well, you get the picture, 3 servers work better and faster than one.